Accurate extraction of surface water extent is a fundamental prerequisite for monitoring its dynamic changes.Although machine learning algorithms have been widely applied to surface water mapping,most studies focus pr...Accurate extraction of surface water extent is a fundamental prerequisite for monitoring its dynamic changes.Although machine learning algorithms have been widely applied to surface water mapping,most studies focus primarily on algorithmic outputs,with limited systematic evaluation of their applicability and constrained classification accuracy.In this study,we focused on the Songnen Plain in Northeast China and employed Sentinel-2 imagery acquired during 2020-2021 via the Google Earth Engine(GEE)platform to evaluate the performance of Classification and Regression Trees(CART),Random Forest(RF),and Support Vector Machine(SVM)for surface water classification.The classification process was optimized by incorporating automated training sample selection and integration of time series features.Validation with independent samples demonstrated the feasibility of automatic sample selection,yielding mean overall accuracies of 91.16%,90.99%,and 90.76%for RF,SVM,and CART,respectively.After integrating time series features,the mean overall accuracies of the three algorithms improved by 4.51%,5.45%,and 6.36%,respectively.In addition,spectral features such as MNDWI(Modified Normalized Difference Water Index),SWIR(Short Wave Infrared),and NDVI(Normalized Difference Vegetation Index)were identified as more important for surface water classification.This study establishes a more consistent framework for surface water mapping,offering new perspectives for improving and automating classification processes in the era of big and open data.展开更多
Separating oil/water mixtures via superhydrophobic stainless steel mesh(SSM)is a kind of efficient methods of treating oily wastewater,and the superhydrophobic SSM with a low cost,simple fabrication process and robust...Separating oil/water mixtures via superhydrophobic stainless steel mesh(SSM)is a kind of efficient methods of treating oily wastewater,and the superhydrophobic SSM with a low cost,simple fabrication process and robust usability remains a challenge.Herein,urushiol-based benzoxazine(U-D)with a strong substrate adhesion and low surface free energy was used to anchor SiO_(2) particles on the SSM surface to obtain a durable superhydrophobic SSM(PU-D/SiO_(2)/SSM)through a simple dip-coating process,meanwhile,epoxy resin was also introduced to further improve the adhesion between coating and SSM.PU-D/SiO_(2)/SSM could successfully separate various immiscible oil-water mixtures with a separation efficiency of over 96%and a flux up to 27100 L/m^(2) h only by gravity,respectively.Especially,the modified SSM could effectively remove water from water-in-oil emulsion with a separation efficiency of 99.7%.Moreover,PU-D/SiO_(2)/SSM had an outstanding reusability,whose water contact angle and separation efficiency only slightly decreased after 20 cycles of separating oil/water mixture.In addition,the modified SSM also displayed a satisfactory abrasion resistance,chemical stability and self-cleaning property.Thereby,the robust PU-D/SiO_(2)/SSM prepared by cheap raw materials and facile dip-coating method exhibits a high potential for separating oil/water mixtures.展开更多
The combination of solar disinfection and photocatalysis technology presents a viable solution for eliminating harmful pathogenic microorganisms from water.However,some photocatalysts(e.g.,zinc oxide-based composites)...The combination of solar disinfection and photocatalysis technology presents a viable solution for eliminating harmful pathogenic microorganisms from water.However,some photocatalysts(e.g.,zinc oxide-based composites)are susceptible to pH-dependent dissolution in water,which can result in the loss of photocatalysts and additional environ-mental pollution.To obtain zinc oxide-based composites with low dissolution and high antibacterial efficiency for pho-tocatalytic water disinfection,we prepared MoS_(2)/ZnO@CS composites via a precipitation method to encapsulate chitosan(CS)around MoS_(2)/ZnO.The amino groups in the CS molecules act as storerooms for hydrogen ions,which inhibits the dissolution of zinc oxide.In addition,the MoS_(2)/ZnO@CS composites exhibit high production of reactive oxygen species(ROS)and broad-spectrum antibacterial activity under simulated solar irradiation(0.1 W·cm^(-2)).This makes it an excellent antibacterial agent for solar disinfection in water treatment.展开更多
Understanding the factors underlying the interaction of water with oxide surfaces is of high technological importance for applications ranging from nuclear fuel safety to heterogeneous catalysis.However,it is a comple...Understanding the factors underlying the interaction of water with oxide surfaces is of high technological importance for applications ranging from nuclear fuel safety to heterogeneous catalysis.However,it is a complex task as numerous different factors(related to the surface and bulk properties)are involved.In the present study,we investigated the characteristics of water adsorption(quantities adsorbed and energetics)on binary oxides of fluorite structure and their mixed oxide combinations(solid solutions).Three representative oxides were chosen,differing in lattice parameter(ionic radius)and oxidation state:ThO_(2)which has a very stable Th^(4+)cation,CeO_(2)in which the cerium cations can be easily reduced to Ce^(3+),and UO_(2)in which the uranium cations tend to further oxidize to U^(5+)and U^(6+).Based on the H_(2)O adsorption isotherms and enthalpies of adsorption versus coverage,combined with X-ray photoelectron spectroscopy(XPS)study of the oxide surface,the main factors underlying the characteristics of water adsorption on the fluorite oxides were identified.The present work points to the importance of oxygen hyper-stoichiometry(in U-containing oxides)on the interaction of water with the oxide’s surface.Furthermore,correlations between Fermi level positioning and water dissociation tendencies are established.This work advances our understanding of water-oxide interactions with implications for material design in energy and environmental systems.展开更多
CuBi_(2)O_(4)is identified as a promising photocathode in photoelectrochemical(PEC)water splitting systems.However,the PEC performance of CuBi_(2)O_(4)is far from expected due to the limited separation and transport e...CuBi_(2)O_(4)is identified as a promising photocathode in photoelectrochemical(PEC)water splitting systems.However,the PEC performance of CuBi_(2)O_(4)is far from expected due to the limited separation and transport efficiency of photogenerated carriers.To address the above issues,a cost-effective ternary Cu:NiO_(X)/CuBi_(2)O_(4)/CuO composite photocathode was designed.Firstly,a thin Cu:NiO_(X)film was inserted between CuBi_(2)O_(4)and FTO conducting substrate as a hole-selective layer,which promotes the transmission of photogenerated holes to the FTO substrate effectively.Furthermore,the modification of CuO film on the CuBi_(2)O_(4)electrode not only increases the absorption of sunlight and generates more photogenerated carriers,but also constitutes a heterojunction with CuBi_(2)O_(4),creating a built-in electric field,which facilitates the separation of electrons and holes,and accelerates the electrons transfer to electrode–electrolyte interface.The fabricated Cu:NiO_(X)/CuBi_(2)O_(4)/CuO composite photocathode exhibits a surprisingly high photocurrent density of−1.51 mA·cm^(−2)at 0.4 V versus RHE,which is 2.6 times that of the pristine CuBi_(2)O_(4)photocathode.The improved PEC performance is attributed to the synergy effect of the Cu:NiO_(X)hole-selective layer and the CuBi_(2)O_(4)/CuO heterojunction.Moreover,the combination with the BiVO_(4)/CoS,an unbiased overall water splitting was achieved,which has a photocurrent of 0.193 mA·cm^(−2).展开更多
In photocatalytic water treatment processes,the particulate photocatalysts are typically immobilized on membrane,through either chemical/physical loading onto the surface or directly embedding in the membrane matrix.H...In photocatalytic water treatment processes,the particulate photocatalysts are typically immobilized on membrane,through either chemical/physical loading onto the surface or directly embedding in the membrane matrix.However,these immobilization strategies inevitably compromise the interfacial mass diffusion and cause activity decline relative to the suspended catalyst.Here,we propose a binder-free surface immobilization strategy for fabrication of high-activity photocatalytic membrane.Through a simple dimethylformamide(DMF)treatment,the nanofibers of polyvinylidene fluoride membrane were softened and stretched,creating enlarged micropores to efficiently capture the photocatalyst.Subsequently,the nanofibers underwent shrinking during DMF evaporation,thus firmly strapping the photocatalyst microparticles on the membrane surface.This surface self-bounded photocatalytic membrane,with firmly bounded yet highly exposed photocatalyst,exhibited 4.2-fold higher efficiency in hydrogen peroxide(H_(2)O_(2))photosynthesis than the matrix-embedded control,due to improved O_(2)accessibility and H_(2)O_(2)diffusion.It even outperformed the suspension photocatalytic system attributed to alleviated H_(2)O_(2)decomposition at the hydrophobic surface.When adopted for UV-based water treatment,the photocatalytic system exhibited tenfold faster micropollutants photodegradation than the catalyst-free control and demonstrated superior robustness for treating contaminated tap water,lake water and secondary wastewater effluent.This immobilization strategy can also be extended to the fabrication of other photocatalytic membranes with diverse catalyst types and membrane substrate.Overall,our work opens a facile avenue for fabrication of high-performance photocatalytic membranes,which may benefit advanced oxidation water purification application and beyond.展开更多
CO_(2) hydrate-based sequestration in submarine sediments shows great potential for carbon emission reduction.Considering the proportional relationship of CO_(2) and water for hydrates formation,their existing ratio l...CO_(2) hydrate-based sequestration in submarine sediments shows great potential for carbon emission reduction.Considering the proportional relationship of CO_(2) and water for hydrates formation,their existing ratio largely determines the CO_(2) sequestration density and phase state.Here,this work focuses on determining the optimal ratio of CO_(2) to seawater in sediments simulated with 20-40 mesh(0.42-0.85 mm) quartz sand,in order to maximize CO_(2) hydrate conversion in sediments.The results show that the conversion rate of CO_(2) hydrate increases with the initial water saturation,reaching 15.3%at 80% initial water saturation.The optimal CO_(2) hydrate formation occurs at 30% initial water saturation,with the corresponding CO_(2) storage density in hydrate form of 33.09 kg·m^(-3) and the hydrate saturation of 22.3%.However,CO_(2) hydrate conversion rate is <10%,which implies that most CO2 still exists in liquid state,despite the presence of free water.The total CO_(2) sequestration density is negatively correlated with the initial water saturation,and at 10% initial water saturation,398.73 kg·m^(-3) of CO_(2) is sequestered,of which only 18.02 kg·m^(-3) is hydrated.Additionally,the lower initial water saturation corresponds to the shorter time to achieve t_(90) of CO_(2) consumption,and the water conversion rate to hydrate reaches 90% at 10% initial water saturation.In summary,adjusting the volume ratio of liquid CO_(2) to seawater can effectively increase the sequestration amount of CO_(2) hydrates,but methods to increase CO_(2) conversion to hydrate still need to be established.展开更多
Exploring earth-abundant,highly active bifunctional electrocatalysts for efficient hydrogen and oxygen evolution is crucial for water splitting.However,due to their distinct free energies and conducting behaviors(elec...Exploring earth-abundant,highly active bifunctional electrocatalysts for efficient hydrogen and oxygen evolution is crucial for water splitting.However,due to their distinct free energies and conducting behaviors(electron/hole),balancing the catalytic efficiency between hydrogen and oxygen evolution remains challenging for achieving bifunctional electrocatalysts.Here,we report a locally-doped MoS_(2)monolayer with an in-plane heterostructure acting as a bifunctional electrocatalyst and apply it to the overall water splitting.In this heterostructure,the core region contains Mo/S vacancies,while the ring region was doped by Fe atoms(in two substitution configurations:1FeMo and 3FeMo-VS clusters)with a p-type conductive characteristic.Our micro-cell measurements,combined with density functional theory(DFT)calculations,reveal that the vacancies-rich core region presents remarkable hydrogen evolution reaction(HER)activity while the Fe-doped ring gives an excellent oxygen evolution reaction(OER)activity,thus forming an in-plane bifunctional electrocatalyst.Finally,as a proof-of-concept for overall water splitting,we constructed a full-cell configuration based on a locally-doped MoS_(2)monolayer,which achieved a cell voltage of 1.87 V at 10 mA·cm^(-2),demonstrating outstanding performance in strong acid electrolytes.Our work provides insight into the hetero-integration of bifunctional electrocatalysts at the atomic level,paving the way for designing transition metal dichalcogenide catalysts with activity-manipulated regions capable of multiple reactions.展开更多
Electrochemical carbon dioxide reduction reaction(CO_(2)RR)produces valuable chemicals by consuming gaseous CO_(2)as well as protons from the electrolyte.Protons,produced by water dissociation in alkaline electrolyte,...Electrochemical carbon dioxide reduction reaction(CO_(2)RR)produces valuable chemicals by consuming gaseous CO_(2)as well as protons from the electrolyte.Protons,produced by water dissociation in alkaline electrolyte,are critical for the reaction kinetics which involves multiple proton coupled electron transfer steps.Herein,we demonstrate that the two key steps(CO_(2)-^(*)COOH and^(*)CO-^(*)COH)efficiency can be precisely tuned by introducing proper amount of water dissociation center,i.e.,Fe single atoms,locally surrounding the Cu catalysts.In alkaline electrolyte,the Faradaic efficiency(FE)of multi-carbon(C^(2+))products exhibited a volcano type plot depending on the density of water dissociation center.A maximum FE for C^(2+)products of 73.2%could be reached on Cu nanoparticles supported on N-doped Carbon nanofibers with moderate Fe single atom sites,at a current density of 300 mA cm^(–2).Experimental and theoretical calculation results reveal that the Fe sites facilitate water dissociation kinetics,and the locally generated protons contribute significantly to the CO_(2)activation and^(*)CO protonation process.On the one hand,in-situ attenuated total reflection surface-enhanced infrared absorption spectroscopy(in-situ ATR-SEIRAS)clearly shows that the^(*)COOH intermediate can be observed at a lower potential.This phenomenon fully demonstrates that the optimized local water dissociation kinetics has a unique advantage in guiding the hydrogenation reaction pathway of CO₂molecules and can effectively reduce the reaction energy barrier.On the other hand,abundant^(*)CO and^(*)COH intermediates create favorable conditions for the asymmetric^(*)CO-^(*)COH coupling,significantly increasing the selectivity of the reaction for C^(2+)products and providing strong support for the efficient conversion of related reactions to the target products.This work provides a promising strategy for the design of a dual sites catalyst to achieve high FE of C^(2+)products through the optimized local water dissociation kinetics.展开更多
Photocatalytic H_(2)production from water splitting is a promising candidate for solving the increasing energy crisis and environmental issues.Herein we report a novel g-C_(3)N_(4)/Ag In_(x)S_(y)S-scheme heterojunctio...Photocatalytic H_(2)production from water splitting is a promising candidate for solving the increasing energy crisis and environmental issues.Herein we report a novel g-C_(3)N_(4)/Ag In_(x)S_(y)S-scheme heterojunction photocatalyst for water splitting into stoichiometric H_(2)and H_(2)O_(2)under visible light.The catalyst was prepared by depositing 3D bimetallic sulfide(Ag In_(x)S_(y))nanotubes onto 2D g-C_(3)N_(4)nanosheets.Owing to the special 3D-on-2D configuration,the photogenerated carriers could be rapidly transferred and effectively separated through the abundant interfacial heterostructures to avoid recombination,and therefore excellent performance for visible light-driven water splitting could be obtained,with a 24-h H_(2)evolution rate up to 237μmol g^(-1)h^(-1).Furthermore,suitable band alignment enables simultaneous H_(2)and H_(2)O_(2)production in a 1:1 stoichiometric ratio.H_(2)and H_(2)O_(2)were evolved on the conduction band of g-C_(3)N_(4)and on the valance band of Ag In_(x)S_(y),respectively.The novel 3D-on-2D configuration for heterojunction construction proposed in this work provided alternative research ideas toward photocatalytic reaction.展开更多
Photoelectrochemical (PEC) hydrogen production holds great promise for applications in energy production. A novel strategy characterized by simplicity, stability, and high efficiency is developed to significantly boos...Photoelectrochemical (PEC) hydrogen production holds great promise for applications in energy production. A novel strategy characterized by simplicity, stability, and high efficiency is developed to significantly boost the PEC performance of TiO_(2) (anatase) nanotube arrays (TNTAs). This strategy entails a series of treatments, including a conventional anodic oxidation (etching) process, a primary annealing treatment, and a secondary annealing treatment via impregnation. As a result, nickel phosphide (Ni_(2)P) is composited onto well-ordered titanium dioxide (anatase) nanotube array photoanodes (Ni_(2)P/TNTAs), which exhibit hugely improved PEC H_(2) generation performance. A thorough and systematic investigation is conducted to comprehensively analyze the morphology, semiconductor band-gap structure, and PEC H_(2) production performance of the Ni_(2)P/TNTAs composites. The experimental results demonstrate that under identical experimental circumstances, the measured photocurrent density of the Ni_(2)P/TNTAs photoanode exhibits a 6.63-fold increase relative to that of TNTAs. The H_(2) production rate of Ni_(2)P/TNTAs reaches 182.96 μmol/cm^(2), 6.10 times higher than that of pure TNTAs. The excellent interfacial charge transfer pathway at the Ni_(2)P/TiO_(2) interface promotes photogenerated carrier separation and electron transfer from TiO_(2) to Ni_(2)P. This method offers a valuable reference for designing highly efficient PEC H_(2)-production catalysts.展开更多
The development of highly active and stable bifunctional electrocatalysts in acidic media is crucial to hydrogen production by proton exchange membrane.In this study,we designed a RuO_(2)-IrO_(2)heterostructure cataly...The development of highly active and stable bifunctional electrocatalysts in acidic media is crucial to hydrogen production by proton exchange membrane.In this study,we designed a RuO_(2)-IrO_(2)heterostructure catalyst coupled by carbon quantum dots(CQDs).The catalyst showed excellent electrocatalytic performance for water splitting under acidic conditions.The overpotentials of oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)were as low as 180 and 15 mV at 10 mA/cm^(2)in 0.5 M H_(2)SO_(4),respectively.The acid electrolytic cell developed with RuO_(2)-IrO_(2)@CQDs as anode and cathode operated stably at 10 m A/cm^(2)for 120 h.In situ measurements and theoretical calculation reveal that the unique lattice oxygen mechanism path of RuO_(2)-IrO_(2)@CQDs can bypass the OOH^(*)intermediate and breaks the linear relationship of adsorbent evolution mechanism path,resulting in higher OER catalytic activity.展开更多
Electrocatalytic CO_(2)reduction reaction(CO_(2)RR)to ethylene(C_(2)H_(4))represents a promising approach to reducing CO_(2)emissions and producing high-value chemicals.The ethylene productivity is always limited by t...Electrocatalytic CO_(2)reduction reaction(CO_(2)RR)to ethylene(C_(2)H_(4))represents a promising approach to reducing CO_(2)emissions and producing high-value chemicals.The ethylene productivity is always limited by the slow reaction kinetics and the high-performance catalysts are significantly desired.Many efforts have been made to develop a catalyst to activate CO_(2)molecules.However,as another reactant,H2O activation does not receive the attention it deserves.In particular,slow H2O dissociation kinetics limit the rate of proton supply,severely impairing the production of C_(2)H_(4).Here,we designed a MgO-modified CuO catalyst(MgO/CuO),which can promote H2O dissociation and enhance CO_(2)adsorption at the same time to realize the efficient ethylene production.The optimal catalyst exhibits a Faraday efficiency for C_(2)H_(4)reached 54.4%at−1.4 V vs.RHE in an H-cell,which is 1.4 times that of pure CuO(37.9%),and it was further enhanced to a 56.7%in a flow cell,with a high current density of up to 535.9 mA cm−2 at−1.0 V vs.RHE.Experimental and theoretical calculations show that MgO/CuO plays a bifunctional role in the CO_(2)RR,which facilitates the adsorption and activation of CO_(2)by CuO and simultaneously accelerates H2O dissociation by MgO doping.The in situ XRD experiments demonstrate that the introduction of MgO protects CuO active phase to avoid overreduction and preserves the active centers for CO_(2)RR.In combination with in situ FTIR and DFT calculations,the protonation process from*CO to*COH and asymmetric C–C coupling step are promoted by the enhanced water activation and proton coupling on MgO/CuO.This work provides new insights into the CO_(2)and H_(2)O coactivation mechanism in CO_(2)RR and a potential universal strategy to design ethylene production electrocatalysts.展开更多
The state-of-the-art anion-exchange membrane water electrolyzers(AEMWEs)require highly stable electrodes for prolonged operation.The stability of the electrode is closely linked to the effective evacuation of H_(2) or...The state-of-the-art anion-exchange membrane water electrolyzers(AEMWEs)require highly stable electrodes for prolonged operation.The stability of the electrode is closely linked to the effective evacuation of H_(2) or O_(2) gas generated from electrode surface during the electrolysis.In this study,we prepared a superhydrophilic electrode by depositing porous nickel–iron nanoparticles on annealed TiO_(2) nanotubes(NiFe/ATNT)for rapid outgassing of such nonpolar gases.The super-hydrophilic NiFe/ATNT electrode exhibited an overpotential of 235 mV at 10 mA cm^(−2) for oxygen evolution reaction in 1.0 M KOH solution,and was utilized as the anode in the AEMWE to achieve a current density of 1.67 A cm^(−2) at 1.80 V.In addition,the AEMWE with NiFe/ATNT electrode,which enables effective outgassing,showed record stability for 1500 h at 0.50 A cm^(−2) under harsh temperature conditions of 80±3℃.展开更多
One of the main challenges in oil-water separation of traditional Chinese medicines(TCM)is to obtain essential oils from the aromatic water of TCM.In this study,silicon dioxide/polyvinylidene fluoride(SiO_(2)/PVDF)mem...One of the main challenges in oil-water separation of traditional Chinese medicines(TCM)is to obtain essential oils from the aromatic water of TCM.In this study,silicon dioxide/polyvinylidene fluoride(SiO_(2)/PVDF)membranes were prepared using nonsolvent induce phase separation.Then polydimethylsiloxane(PDMS)was coated to obtain PDMS/SiO_(2/)PVDF membranes.Separated essential oils and water from aromatic water in the gaseous state by vapor permeation membrane separation technology.The relationship between membrane structure and membrane separation effect was investigated.Response surface methodology was used to develop a quadratic model for the separation factor,membrane permeation separation index and membrane preparation process.The optimal process parameters for the membrane separation were 12.31%(mass)concentration of PVDF solution,9.6%(mass)of N,Ndimethylacetamide in the solidification bath,and 0.2 g hydrophobic nano-SiO_(2)incorporation,with a separation factor of 14.45,and a membrane flux of 1203.04 g·m^(-2)·h^(-1).Compared with the PDMS/PVDF membranes,the separation factor and membrane flux were increased by 68.59%and 3.46%,respectively.Compared with the SiO_(2)/PVDF membranes,the separation factor and membrane flux were increased by478%and 79.33%,respectively.Effectively mitigated the limitations of traditional polymer membrane material performance affected by the"trade-off"effect.Attenuated total internal reflection-Fourier transform infrared spectroscopy,contact angle,scanning electron microscopy and energy dispersive spectroscopy were used to characterize the PDMS/SiO_(2)/PVDF membranes,and gas chromatography was used to characterize the permeate.In addition,the contents of L-menthol,L-menthone,menthyl acetate and limonene in the permeate,conformed to the European Pharmacopoeia standards.This study provided an effective preparation strategy of a feasible hydrophobic powder polymer membrane for the separation of essential oils from gaseous peppermint aromatic water.展开更多
Developing efficient and stable catalysts for the hydrogen evolution reaction(HER)is essential for advancing anion-exchange membrane water electrolyzer(AEMWE)technology.In this study,we present a facile microwave redu...Developing efficient and stable catalysts for the hydrogen evolution reaction(HER)is essential for advancing anion-exchange membrane water electrolyzer(AEMWE)technology.In this study,we present a facile microwave reduction and low-temperature phosphorization strategy to synthesize a highly efficient HER catalyst,comprising P,N-codoped carbon-supported RuP_(2)nanocluster(RuP_(2)@PNC).RuP_(2)@PNC demonstrates outstanding HER performance,achieving overpotentials of 18 and 44 mV at a current density of 10 mA cm^(-2)in alkaline and acidic media,respectively.Furthermore,an AEMWE device utilizing RuP_(2)@PNC as the cathode catalyst delivers a current density of 0.5 A cm^(-2)at a cell voltage of 1.84 V and exhibits remarkable stability over 150 h of operation.Experimental analyses and density functional theory(DFT)calculations reveal that the synergistic effects of P,N-codoped and the unique structure of RuP_(2)enhance electron transfer between Ru and the support,optimize the electronic structure,and regulate the d–band center of Ru.These features improve water adsorption,weaken the Ru–H binding strength,and facilitate efficient H_(2)desorption,collectively driving the superior HER activity of RuP_(2)@PNC.This work offers an effective design strategy for high-performance HER catalysts and provides valuable insights for accelerating the development of AEMWE technology.展开更多
Herein,UiO-66-NH_(2) nanoparticles were solvothermally immobilized onto Zn_(0.4)Cd_(0.6)S nanorods in varying amounts.The resulting UiO-66-NH_(2)/Zn_(0.4)Cd_(0.6)S hybrid architectures demonstrated UiO-66-NH_(2) conte...Herein,UiO-66-NH_(2) nanoparticles were solvothermally immobilized onto Zn_(0.4)Cd_(0.6)S nanorods in varying amounts.The resulting UiO-66-NH_(2)/Zn_(0.4)Cd_(0.6)S hybrid architectures demonstrated UiO-66-NH_(2) contentdependent photocatalytic activity for visible-light-driven hydrogen peroxide(H_(2)O_(2))production from pure water.Notably,the optimized UiO-66-NH_(2)/Zn_(0.4)Cd_(0.6)S-0.2 catalyst achieved the highest H_(2)O_(2) yield under visible-light illumination,surpassing those of pure UiO-66-NH_(2) and bare Zn_(0.4)Cd_(0.6)S by factors of 81.12 and 2.22,respectively.In addition,the UiO-66-NH_(2)/Zn_(0.4)Cd_(0.6)S-0.2 sample exhibited outstanding photocatalytic efficiency,achieving an NH3 concentration of 25.02±0.68 mg L^(−1) after 1 h of visible-light exposure and an H_(2) evolution of 487.12 mmol g^(−1) following 3 h of irradiation.The notable enhancement in the photocatalytic performance was attributed to efficient S-scheme charge transfer,as confirmed by transient absorption spectroscopy.The S-scheme charge migration mechanism in the UiO-66-NH_(2)/Zn_(0.4)Cd_(0.6)S system was further validated by electron paramagnetic resonance,density functional theory calculations,and in situ irradiated X-ray photoelectron spectroscopy.Overall,this study presents a promising strategy for designing highly efficient hybrid architectures for photocatalytic applications.展开更多
Photoelectrochemical water oxidation(PEC-WO)as a green and sustainable route to produce H_(2)O_(2)has attracted extensive attentions.However,water oxidation to H_(2)O_(2)via a 2e^(-) pathway is thermodynamically more ...Photoelectrochemical water oxidation(PEC-WO)as a green and sustainable route to produce H_(2)O_(2)has attracted extensive attentions.However,water oxidation to H_(2)O_(2)via a 2e^(-) pathway is thermodynamically more difficult than to O_(2)via a 4e^(-)pathway.Herein,with a series of BiVO_(4)-based photoanodes,the decisive factors determining the PEC activity and selectivity are elucidated,combining a comprehensive experimental and theoretical investigations.It is discovered that the ZnO/BiVO_(4)photoanode(ZnO/BVO)forms a Type-Ⅱheterojunction in energy level alignment.The accelerated photogenerated charge separation/transfer dynamics generates denser surface holes and higher surface photovoltage.Therefore,the activity of water oxidation reaction is promoted.The selectivity of PEC-WO to H_(2)O_(2)is found to be potential-dependent,i.e.,at the lower potentials(PEC-dominated),surface hole density determines the selectivity;and at the higher potentials(electrochemical-dominated),surface reaction barriers govern the selectivity.For the ZnO/BVO heterojunction photoanode,the higher surface hole density facilitates the generation of OH·and the subsequent OH·/OH·coupling to form H_(2)O_(2),thus rising up with potentials;at the higher potentials,the 2-electron pathway barrier over ZnO/BVO surface is lower than over BVO surface,which benefits from the electronic structure regulation by the underlying ZnO alleviating the over-strong adsorption of^(*)OH on BVO,thus,the two-electron pathway to produce H_(2)O_(2)is more favored than on BVO surface.This work highlights the crucial role of band energy structure of semiconductors on both PEC reaction activity and selectivity,and the knowledge gained is expected to be extended to other photoeletrochemical reactions.展开更多
The oxygen evolution reaction(OER)is the bottleneck in the overall photocatalytic splitting of water.The active sites(terminal titanium or bridging oxygen)and active species(molecular or dissociative water)of the init...The oxygen evolution reaction(OER)is the bottleneck in the overall photocatalytic splitting of water.The active sites(terminal titanium or bridging oxygen)and active species(molecular or dissociative water)of the initial step of the photocatalyzed OER on the prototypical photocatalyst TiO_(2),remain debatable.Herein,the photocatalytic chemistry of monolayer water on oxygen-pretreated TiO_(2)(110)(o-TiO_(2)(110))and reduced TiO_(2)(110)(r-TiO_(2)(110))surfaces initiated by 400 nm light illumination was investigated by time-dependent two-photon photoemission spectroscopy(TD-2PPE).The photoinduced reduction of the H_(2)O/o-TiO_(2)(110)interface rather than the H2O/r-TiO_(2)(110)interface was detected by TD-2PPE.The difference in 2PPE originated from the presence of the terminal hydroxyl anions(OHt^(-))on H_(2)O/o-TiO_(2)(110),as identified by X-ray photoelectron spectroscopy and temperature-programmed desorption.Therefore,the evolution of the electronic structure of H_(2)O/o-TiO_(2)(110)was attributed to the photocatalyzed oxidation of the terminal hydroxyl anions,which most likely formed gaseous·OH radicals,reducing the interface.This work suggested that the oxidation of hydroxyl anions on top of the terminal titanium ions on TiO_(2),which were excluded previously in solution,need to be considered in the mechanistic studies of the photocatalyzed OER.展开更多
基金Under the auspices of National Key R&D Program of China(No.2024YFF1306405)。
文摘Accurate extraction of surface water extent is a fundamental prerequisite for monitoring its dynamic changes.Although machine learning algorithms have been widely applied to surface water mapping,most studies focus primarily on algorithmic outputs,with limited systematic evaluation of their applicability and constrained classification accuracy.In this study,we focused on the Songnen Plain in Northeast China and employed Sentinel-2 imagery acquired during 2020-2021 via the Google Earth Engine(GEE)platform to evaluate the performance of Classification and Regression Trees(CART),Random Forest(RF),and Support Vector Machine(SVM)for surface water classification.The classification process was optimized by incorporating automated training sample selection and integration of time series features.Validation with independent samples demonstrated the feasibility of automatic sample selection,yielding mean overall accuracies of 91.16%,90.99%,and 90.76%for RF,SVM,and CART,respectively.After integrating time series features,the mean overall accuracies of the three algorithms improved by 4.51%,5.45%,and 6.36%,respectively.In addition,spectral features such as MNDWI(Modified Normalized Difference Water Index),SWIR(Short Wave Infrared),and NDVI(Normalized Difference Vegetation Index)were identified as more important for surface water classification.This study establishes a more consistent framework for surface water mapping,offering new perspectives for improving and automating classification processes in the era of big and open data.
基金Funded by the National Natural Science Foundation of China(No.22165019)。
文摘Separating oil/water mixtures via superhydrophobic stainless steel mesh(SSM)is a kind of efficient methods of treating oily wastewater,and the superhydrophobic SSM with a low cost,simple fabrication process and robust usability remains a challenge.Herein,urushiol-based benzoxazine(U-D)with a strong substrate adhesion and low surface free energy was used to anchor SiO_(2) particles on the SSM surface to obtain a durable superhydrophobic SSM(PU-D/SiO_(2)/SSM)through a simple dip-coating process,meanwhile,epoxy resin was also introduced to further improve the adhesion between coating and SSM.PU-D/SiO_(2)/SSM could successfully separate various immiscible oil-water mixtures with a separation efficiency of over 96%and a flux up to 27100 L/m^(2) h only by gravity,respectively.Especially,the modified SSM could effectively remove water from water-in-oil emulsion with a separation efficiency of 99.7%.Moreover,PU-D/SiO_(2)/SSM had an outstanding reusability,whose water contact angle and separation efficiency only slightly decreased after 20 cycles of separating oil/water mixture.In addition,the modified SSM also displayed a satisfactory abrasion resistance,chemical stability and self-cleaning property.Thereby,the robust PU-D/SiO_(2)/SSM prepared by cheap raw materials and facile dip-coating method exhibits a high potential for separating oil/water mixtures.
基金supported in part by the National Natural Science Foundation of China(12174366)Fundamental Re-search Funds for the Central Universities(WK3450000005)the Anhui Provincial Natural Science Foundation(2108085MC93).
文摘The combination of solar disinfection and photocatalysis technology presents a viable solution for eliminating harmful pathogenic microorganisms from water.However,some photocatalysts(e.g.,zinc oxide-based composites)are susceptible to pH-dependent dissolution in water,which can result in the loss of photocatalysts and additional environ-mental pollution.To obtain zinc oxide-based composites with low dissolution and high antibacterial efficiency for pho-tocatalytic water disinfection,we prepared MoS_(2)/ZnO@CS composites via a precipitation method to encapsulate chitosan(CS)around MoS_(2)/ZnO.The amino groups in the CS molecules act as storerooms for hydrogen ions,which inhibits the dissolution of zinc oxide.In addition,the MoS_(2)/ZnO@CS composites exhibit high production of reactive oxygen species(ROS)and broad-spectrum antibacterial activity under simulated solar irradiation(0.1 W·cm^(-2)).This makes it an excellent antibacterial agent for solar disinfection in water treatment.
基金Open access funding provided by Ben-Gurion University
文摘Understanding the factors underlying the interaction of water with oxide surfaces is of high technological importance for applications ranging from nuclear fuel safety to heterogeneous catalysis.However,it is a complex task as numerous different factors(related to the surface and bulk properties)are involved.In the present study,we investigated the characteristics of water adsorption(quantities adsorbed and energetics)on binary oxides of fluorite structure and their mixed oxide combinations(solid solutions).Three representative oxides were chosen,differing in lattice parameter(ionic radius)and oxidation state:ThO_(2)which has a very stable Th^(4+)cation,CeO_(2)in which the cerium cations can be easily reduced to Ce^(3+),and UO_(2)in which the uranium cations tend to further oxidize to U^(5+)and U^(6+).Based on the H_(2)O adsorption isotherms and enthalpies of adsorption versus coverage,combined with X-ray photoelectron spectroscopy(XPS)study of the oxide surface,the main factors underlying the characteristics of water adsorption on the fluorite oxides were identified.The present work points to the importance of oxygen hyper-stoichiometry(in U-containing oxides)on the interaction of water with the oxide’s surface.Furthermore,correlations between Fermi level positioning and water dissociation tendencies are established.This work advances our understanding of water-oxide interactions with implications for material design in energy and environmental systems.
基金supported by the National Natural Science Foundation of China(No.61804039)the University Natural Sciences Research Project of Anhui Province(No.2022AH010096)+1 种基金the Talent Research Fund of Hefei University(No.20RC35)the Natural Science Foundation of Anhui Higher Education Institution of China(No.2023AH040160).
文摘CuBi_(2)O_(4)is identified as a promising photocathode in photoelectrochemical(PEC)water splitting systems.However,the PEC performance of CuBi_(2)O_(4)is far from expected due to the limited separation and transport efficiency of photogenerated carriers.To address the above issues,a cost-effective ternary Cu:NiO_(X)/CuBi_(2)O_(4)/CuO composite photocathode was designed.Firstly,a thin Cu:NiO_(X)film was inserted between CuBi_(2)O_(4)and FTO conducting substrate as a hole-selective layer,which promotes the transmission of photogenerated holes to the FTO substrate effectively.Furthermore,the modification of CuO film on the CuBi_(2)O_(4)electrode not only increases the absorption of sunlight and generates more photogenerated carriers,but also constitutes a heterojunction with CuBi_(2)O_(4),creating a built-in electric field,which facilitates the separation of electrons and holes,and accelerates the electrons transfer to electrode–electrolyte interface.The fabricated Cu:NiO_(X)/CuBi_(2)O_(4)/CuO composite photocathode exhibits a surprisingly high photocurrent density of−1.51 mA·cm^(−2)at 0.4 V versus RHE,which is 2.6 times that of the pristine CuBi_(2)O_(4)photocathode.The improved PEC performance is attributed to the synergy effect of the Cu:NiO_(X)hole-selective layer and the CuBi_(2)O_(4)/CuO heterojunction.Moreover,the combination with the BiVO_(4)/CoS,an unbiased overall water splitting was achieved,which has a photocurrent of 0.193 mA·cm^(−2).
基金supported by the National Key R&D Program of China(2024YFA1211004)the National Natural Science Foundation of China(52300069,52192681,U21A20160)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20230276)Science and Technology Program of Suzhou,China(SWY20222003,2022SS19).
文摘In photocatalytic water treatment processes,the particulate photocatalysts are typically immobilized on membrane,through either chemical/physical loading onto the surface or directly embedding in the membrane matrix.However,these immobilization strategies inevitably compromise the interfacial mass diffusion and cause activity decline relative to the suspended catalyst.Here,we propose a binder-free surface immobilization strategy for fabrication of high-activity photocatalytic membrane.Through a simple dimethylformamide(DMF)treatment,the nanofibers of polyvinylidene fluoride membrane were softened and stretched,creating enlarged micropores to efficiently capture the photocatalyst.Subsequently,the nanofibers underwent shrinking during DMF evaporation,thus firmly strapping the photocatalyst microparticles on the membrane surface.This surface self-bounded photocatalytic membrane,with firmly bounded yet highly exposed photocatalyst,exhibited 4.2-fold higher efficiency in hydrogen peroxide(H_(2)O_(2))photosynthesis than the matrix-embedded control,due to improved O_(2)accessibility and H_(2)O_(2)diffusion.It even outperformed the suspension photocatalytic system attributed to alleviated H_(2)O_(2)decomposition at the hydrophobic surface.When adopted for UV-based water treatment,the photocatalytic system exhibited tenfold faster micropollutants photodegradation than the catalyst-free control and demonstrated superior robustness for treating contaminated tap water,lake water and secondary wastewater effluent.This immobilization strategy can also be extended to the fabrication of other photocatalytic membranes with diverse catalyst types and membrane substrate.Overall,our work opens a facile avenue for fabrication of high-performance photocatalytic membranes,which may benefit advanced oxidation water purification application and beyond.
基金financially supported by the National Natural Science Foundation of China (22378424,22127812)the Science Foundation of China University of Petroleum Beijing,China (2462023BJRC017)。
文摘CO_(2) hydrate-based sequestration in submarine sediments shows great potential for carbon emission reduction.Considering the proportional relationship of CO_(2) and water for hydrates formation,their existing ratio largely determines the CO_(2) sequestration density and phase state.Here,this work focuses on determining the optimal ratio of CO_(2) to seawater in sediments simulated with 20-40 mesh(0.42-0.85 mm) quartz sand,in order to maximize CO_(2) hydrate conversion in sediments.The results show that the conversion rate of CO_(2) hydrate increases with the initial water saturation,reaching 15.3%at 80% initial water saturation.The optimal CO_(2) hydrate formation occurs at 30% initial water saturation,with the corresponding CO_(2) storage density in hydrate form of 33.09 kg·m^(-3) and the hydrate saturation of 22.3%.However,CO_(2) hydrate conversion rate is <10%,which implies that most CO2 still exists in liquid state,despite the presence of free water.The total CO_(2) sequestration density is negatively correlated with the initial water saturation,and at 10% initial water saturation,398.73 kg·m^(-3) of CO_(2) is sequestered,of which only 18.02 kg·m^(-3) is hydrated.Additionally,the lower initial water saturation corresponds to the shorter time to achieve t_(90) of CO_(2) consumption,and the water conversion rate to hydrate reaches 90% at 10% initial water saturation.In summary,adjusting the volume ratio of liquid CO_(2) to seawater can effectively increase the sequestration amount of CO_(2) hydrates,but methods to increase CO_(2) conversion to hydrate still need to be established.
基金supported by the National Natural Science Foundation of China(Nos.22175060 and 22376062)JSPS Grant-in-Aid for Scientific Research(Nos.JP21H05235,JP22H05478 and JP22F22358)+1 种基金China Postdoctoral Science Foundation(No.2022M722867)the Key Research Project of Higher Education Institutions in Henan Province(No.23A530001).
文摘Exploring earth-abundant,highly active bifunctional electrocatalysts for efficient hydrogen and oxygen evolution is crucial for water splitting.However,due to their distinct free energies and conducting behaviors(electron/hole),balancing the catalytic efficiency between hydrogen and oxygen evolution remains challenging for achieving bifunctional electrocatalysts.Here,we report a locally-doped MoS_(2)monolayer with an in-plane heterostructure acting as a bifunctional electrocatalyst and apply it to the overall water splitting.In this heterostructure,the core region contains Mo/S vacancies,while the ring region was doped by Fe atoms(in two substitution configurations:1FeMo and 3FeMo-VS clusters)with a p-type conductive characteristic.Our micro-cell measurements,combined with density functional theory(DFT)calculations,reveal that the vacancies-rich core region presents remarkable hydrogen evolution reaction(HER)activity while the Fe-doped ring gives an excellent oxygen evolution reaction(OER)activity,thus forming an in-plane bifunctional electrocatalyst.Finally,as a proof-of-concept for overall water splitting,we constructed a full-cell configuration based on a locally-doped MoS_(2)monolayer,which achieved a cell voltage of 1.87 V at 10 mA·cm^(-2),demonstrating outstanding performance in strong acid electrolytes.Our work provides insight into the hetero-integration of bifunctional electrocatalysts at the atomic level,paving the way for designing transition metal dichalcogenide catalysts with activity-manipulated regions capable of multiple reactions.
文摘Electrochemical carbon dioxide reduction reaction(CO_(2)RR)produces valuable chemicals by consuming gaseous CO_(2)as well as protons from the electrolyte.Protons,produced by water dissociation in alkaline electrolyte,are critical for the reaction kinetics which involves multiple proton coupled electron transfer steps.Herein,we demonstrate that the two key steps(CO_(2)-^(*)COOH and^(*)CO-^(*)COH)efficiency can be precisely tuned by introducing proper amount of water dissociation center,i.e.,Fe single atoms,locally surrounding the Cu catalysts.In alkaline electrolyte,the Faradaic efficiency(FE)of multi-carbon(C^(2+))products exhibited a volcano type plot depending on the density of water dissociation center.A maximum FE for C^(2+)products of 73.2%could be reached on Cu nanoparticles supported on N-doped Carbon nanofibers with moderate Fe single atom sites,at a current density of 300 mA cm^(–2).Experimental and theoretical calculation results reveal that the Fe sites facilitate water dissociation kinetics,and the locally generated protons contribute significantly to the CO_(2)activation and^(*)CO protonation process.On the one hand,in-situ attenuated total reflection surface-enhanced infrared absorption spectroscopy(in-situ ATR-SEIRAS)clearly shows that the^(*)COOH intermediate can be observed at a lower potential.This phenomenon fully demonstrates that the optimized local water dissociation kinetics has a unique advantage in guiding the hydrogenation reaction pathway of CO₂molecules and can effectively reduce the reaction energy barrier.On the other hand,abundant^(*)CO and^(*)COH intermediates create favorable conditions for the asymmetric^(*)CO-^(*)COH coupling,significantly increasing the selectivity of the reaction for C^(2+)products and providing strong support for the efficient conversion of related reactions to the target products.This work provides a promising strategy for the design of a dual sites catalyst to achieve high FE of C^(2+)products through the optimized local water dissociation kinetics.
基金financially supported by the National Natural Science Foundation of China(Nos.52362012,42077162,51978323)Natural Science Foundation of Jiangxi Province(No.2022ACB203014)+4 种基金Major Discipline Academic and Technical Leaders Training Program of Jiangxi Province(Nos.20213BCJ22018,20232BCJ22048)Natural Science Project of the Educational Department in Jiangxi Province(No.GJJ2201121)Natural Science Foundation of Nanchang Hangkong University(No.EA202202256)Educational Reform Project of Jiangxi Province(No.JXYJG-2022-135)Nanchang Hangkong University Educational Reform Project(Nos.sz2214,sz2213,JY22017,KCPY1806)。
文摘Photocatalytic H_(2)production from water splitting is a promising candidate for solving the increasing energy crisis and environmental issues.Herein we report a novel g-C_(3)N_(4)/Ag In_(x)S_(y)S-scheme heterojunction photocatalyst for water splitting into stoichiometric H_(2)and H_(2)O_(2)under visible light.The catalyst was prepared by depositing 3D bimetallic sulfide(Ag In_(x)S_(y))nanotubes onto 2D g-C_(3)N_(4)nanosheets.Owing to the special 3D-on-2D configuration,the photogenerated carriers could be rapidly transferred and effectively separated through the abundant interfacial heterostructures to avoid recombination,and therefore excellent performance for visible light-driven water splitting could be obtained,with a 24-h H_(2)evolution rate up to 237μmol g^(-1)h^(-1).Furthermore,suitable band alignment enables simultaneous H_(2)and H_(2)O_(2)production in a 1:1 stoichiometric ratio.H_(2)and H_(2)O_(2)were evolved on the conduction band of g-C_(3)N_(4)and on the valance band of Ag In_(x)S_(y),respectively.The novel 3D-on-2D configuration for heterojunction construction proposed in this work provided alternative research ideas toward photocatalytic reaction.
基金financial support of the Natural Science Foundation of Fujian Province(2023H0046)the XMIREM autonomously deployment project(2023CX10,2023GG01)+3 种基金the Science and Technology Service Network Initiative from Chinese Academy of Science(STS2024T3071)the National Natural Science Foundation of China(22275185,22272069,22472074)the Major Research Project of Xiamen(3502Z20191015)the Fujian Science&Technology Innovation Laboratory for Optoelectronic Information。
文摘Photoelectrochemical (PEC) hydrogen production holds great promise for applications in energy production. A novel strategy characterized by simplicity, stability, and high efficiency is developed to significantly boost the PEC performance of TiO_(2) (anatase) nanotube arrays (TNTAs). This strategy entails a series of treatments, including a conventional anodic oxidation (etching) process, a primary annealing treatment, and a secondary annealing treatment via impregnation. As a result, nickel phosphide (Ni_(2)P) is composited onto well-ordered titanium dioxide (anatase) nanotube array photoanodes (Ni_(2)P/TNTAs), which exhibit hugely improved PEC H_(2) generation performance. A thorough and systematic investigation is conducted to comprehensively analyze the morphology, semiconductor band-gap structure, and PEC H_(2) production performance of the Ni_(2)P/TNTAs composites. The experimental results demonstrate that under identical experimental circumstances, the measured photocurrent density of the Ni_(2)P/TNTAs photoanode exhibits a 6.63-fold increase relative to that of TNTAs. The H_(2) production rate of Ni_(2)P/TNTAs reaches 182.96 μmol/cm^(2), 6.10 times higher than that of pure TNTAs. The excellent interfacial charge transfer pathway at the Ni_(2)P/TiO_(2) interface promotes photogenerated carrier separation and electron transfer from TiO_(2) to Ni_(2)P. This method offers a valuable reference for designing highly efficient PEC H_(2)-production catalysts.
基金supported by the Natural Science Foundation of Shandong Province ZR2024MB087the National Natural Science Foundation of China(No.52122308,51973200,52202050,and 21905253)+3 种基金the Natural Science Foundation of Henan(202300410372)the Joint Fund of Science and Technology R&D Plan of Henan Province(232301420042)the China Postdoctoral Science Foundation(2022TQ0286)the Center for Modern Analysis and Gene Sequencing of Zhengzhou University for supporting this project。
文摘The development of highly active and stable bifunctional electrocatalysts in acidic media is crucial to hydrogen production by proton exchange membrane.In this study,we designed a RuO_(2)-IrO_(2)heterostructure catalyst coupled by carbon quantum dots(CQDs).The catalyst showed excellent electrocatalytic performance for water splitting under acidic conditions.The overpotentials of oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)were as low as 180 and 15 mV at 10 mA/cm^(2)in 0.5 M H_(2)SO_(4),respectively.The acid electrolytic cell developed with RuO_(2)-IrO_(2)@CQDs as anode and cathode operated stably at 10 m A/cm^(2)for 120 h.In situ measurements and theoretical calculation reveal that the unique lattice oxygen mechanism path of RuO_(2)-IrO_(2)@CQDs can bypass the OOH^(*)intermediate and breaks the linear relationship of adsorbent evolution mechanism path,resulting in higher OER catalytic activity.
基金supported by the National Natural Science Foundation of China(Grant No.U21B2099,U22A20425,and 22208377)Natural Science Foundation of Shandong Province(ZR2021QE062)Fundamental Research Funds for the Central Universities,Ocean University of China(grant number 202364004)。
文摘Electrocatalytic CO_(2)reduction reaction(CO_(2)RR)to ethylene(C_(2)H_(4))represents a promising approach to reducing CO_(2)emissions and producing high-value chemicals.The ethylene productivity is always limited by the slow reaction kinetics and the high-performance catalysts are significantly desired.Many efforts have been made to develop a catalyst to activate CO_(2)molecules.However,as another reactant,H2O activation does not receive the attention it deserves.In particular,slow H2O dissociation kinetics limit the rate of proton supply,severely impairing the production of C_(2)H_(4).Here,we designed a MgO-modified CuO catalyst(MgO/CuO),which can promote H2O dissociation and enhance CO_(2)adsorption at the same time to realize the efficient ethylene production.The optimal catalyst exhibits a Faraday efficiency for C_(2)H_(4)reached 54.4%at−1.4 V vs.RHE in an H-cell,which is 1.4 times that of pure CuO(37.9%),and it was further enhanced to a 56.7%in a flow cell,with a high current density of up to 535.9 mA cm−2 at−1.0 V vs.RHE.Experimental and theoretical calculations show that MgO/CuO plays a bifunctional role in the CO_(2)RR,which facilitates the adsorption and activation of CO_(2)by CuO and simultaneously accelerates H2O dissociation by MgO doping.The in situ XRD experiments demonstrate that the introduction of MgO protects CuO active phase to avoid overreduction and preserves the active centers for CO_(2)RR.In combination with in situ FTIR and DFT calculations,the protonation process from*CO to*COH and asymmetric C–C coupling step are promoted by the enhanced water activation and proton coupling on MgO/CuO.This work provides new insights into the CO_(2)and H_(2)O coactivation mechanism in CO_(2)RR and a potential universal strategy to design ethylene production electrocatalysts.
基金supported by the National Research Foundation of Korea(RS-2023-00207831,RS-2024-00346153).
文摘The state-of-the-art anion-exchange membrane water electrolyzers(AEMWEs)require highly stable electrodes for prolonged operation.The stability of the electrode is closely linked to the effective evacuation of H_(2) or O_(2) gas generated from electrode surface during the electrolysis.In this study,we prepared a superhydrophilic electrode by depositing porous nickel–iron nanoparticles on annealed TiO_(2) nanotubes(NiFe/ATNT)for rapid outgassing of such nonpolar gases.The super-hydrophilic NiFe/ATNT electrode exhibited an overpotential of 235 mV at 10 mA cm^(−2) for oxygen evolution reaction in 1.0 M KOH solution,and was utilized as the anode in the AEMWE to achieve a current density of 1.67 A cm^(−2) at 1.80 V.In addition,the AEMWE with NiFe/ATNT electrode,which enables effective outgassing,showed record stability for 1500 h at 0.50 A cm^(−2) under harsh temperature conditions of 80±3℃.
基金supported by the National Natural Science Foundation of China(22478007)the National Key Research and Development Program of China(2022YFB3805100)the Anhui Provincial Natural Science Foundation(2023AH050728)。
文摘One of the main challenges in oil-water separation of traditional Chinese medicines(TCM)is to obtain essential oils from the aromatic water of TCM.In this study,silicon dioxide/polyvinylidene fluoride(SiO_(2)/PVDF)membranes were prepared using nonsolvent induce phase separation.Then polydimethylsiloxane(PDMS)was coated to obtain PDMS/SiO_(2/)PVDF membranes.Separated essential oils and water from aromatic water in the gaseous state by vapor permeation membrane separation technology.The relationship between membrane structure and membrane separation effect was investigated.Response surface methodology was used to develop a quadratic model for the separation factor,membrane permeation separation index and membrane preparation process.The optimal process parameters for the membrane separation were 12.31%(mass)concentration of PVDF solution,9.6%(mass)of N,Ndimethylacetamide in the solidification bath,and 0.2 g hydrophobic nano-SiO_(2)incorporation,with a separation factor of 14.45,and a membrane flux of 1203.04 g·m^(-2)·h^(-1).Compared with the PDMS/PVDF membranes,the separation factor and membrane flux were increased by 68.59%and 3.46%,respectively.Compared with the SiO_(2)/PVDF membranes,the separation factor and membrane flux were increased by478%and 79.33%,respectively.Effectively mitigated the limitations of traditional polymer membrane material performance affected by the"trade-off"effect.Attenuated total internal reflection-Fourier transform infrared spectroscopy,contact angle,scanning electron microscopy and energy dispersive spectroscopy were used to characterize the PDMS/SiO_(2)/PVDF membranes,and gas chromatography was used to characterize the permeate.In addition,the contents of L-menthol,L-menthone,menthyl acetate and limonene in the permeate,conformed to the European Pharmacopoeia standards.This study provided an effective preparation strategy of a feasible hydrophobic powder polymer membrane for the separation of essential oils from gaseous peppermint aromatic water.
基金supported by the National Natural Science Foundation of China(Nos.52371222 and 52271211)the Natural Science Foundation of Hunan Province in China(Nos.2025JJ60350,2024JJ4022,and 2023JJ30277)+1 种基金the Key Research and Development Program of Hunan Province(No.2023GK2035)HORIZON–Marie Sk?odowska–Curie Actions–2021–PF(No.101065098),European Union
文摘Developing efficient and stable catalysts for the hydrogen evolution reaction(HER)is essential for advancing anion-exchange membrane water electrolyzer(AEMWE)technology.In this study,we present a facile microwave reduction and low-temperature phosphorization strategy to synthesize a highly efficient HER catalyst,comprising P,N-codoped carbon-supported RuP_(2)nanocluster(RuP_(2)@PNC).RuP_(2)@PNC demonstrates outstanding HER performance,achieving overpotentials of 18 and 44 mV at a current density of 10 mA cm^(-2)in alkaline and acidic media,respectively.Furthermore,an AEMWE device utilizing RuP_(2)@PNC as the cathode catalyst delivers a current density of 0.5 A cm^(-2)at a cell voltage of 1.84 V and exhibits remarkable stability over 150 h of operation.Experimental analyses and density functional theory(DFT)calculations reveal that the synergistic effects of P,N-codoped and the unique structure of RuP_(2)enhance electron transfer between Ru and the support,optimize the electronic structure,and regulate the d–band center of Ru.These features improve water adsorption,weaken the Ru–H binding strength,and facilitate efficient H_(2)desorption,collectively driving the superior HER activity of RuP_(2)@PNC.This work offers an effective design strategy for high-performance HER catalysts and provides valuable insights for accelerating the development of AEMWE technology.
基金supported by the Natural Science Foundation of Zhejiang Province(LTGS24E020001,LZY24E020001)National Natural Science Foundation of China(52102288)+1 种基金the Project for Science and Technology Innovation Leading Talents of Zhejiang Provincial High-level Talents Special Support Plan(2021R52028)Open Foundation of State Key Laboratory of Environmental Criteria and Risk Assessment,Chinese Research Academy of Environmental Sciences(SKLECRA2022OFP03).
文摘Herein,UiO-66-NH_(2) nanoparticles were solvothermally immobilized onto Zn_(0.4)Cd_(0.6)S nanorods in varying amounts.The resulting UiO-66-NH_(2)/Zn_(0.4)Cd_(0.6)S hybrid architectures demonstrated UiO-66-NH_(2) contentdependent photocatalytic activity for visible-light-driven hydrogen peroxide(H_(2)O_(2))production from pure water.Notably,the optimized UiO-66-NH_(2)/Zn_(0.4)Cd_(0.6)S-0.2 catalyst achieved the highest H_(2)O_(2) yield under visible-light illumination,surpassing those of pure UiO-66-NH_(2) and bare Zn_(0.4)Cd_(0.6)S by factors of 81.12 and 2.22,respectively.In addition,the UiO-66-NH_(2)/Zn_(0.4)Cd_(0.6)S-0.2 sample exhibited outstanding photocatalytic efficiency,achieving an NH3 concentration of 25.02±0.68 mg L^(−1) after 1 h of visible-light exposure and an H_(2) evolution of 487.12 mmol g^(−1) following 3 h of irradiation.The notable enhancement in the photocatalytic performance was attributed to efficient S-scheme charge transfer,as confirmed by transient absorption spectroscopy.The S-scheme charge migration mechanism in the UiO-66-NH_(2)/Zn_(0.4)Cd_(0.6)S system was further validated by electron paramagnetic resonance,density functional theory calculations,and in situ irradiated X-ray photoelectron spectroscopy.Overall,this study presents a promising strategy for designing highly efficient hybrid architectures for photocatalytic applications.
基金financially supported by the National Natural Science Foundation of China(22478211,22179067,22372017)the Major Fundamental Research Program of Natural Science Foundation of Shandong Province(ZR2022ZD10)。
文摘Photoelectrochemical water oxidation(PEC-WO)as a green and sustainable route to produce H_(2)O_(2)has attracted extensive attentions.However,water oxidation to H_(2)O_(2)via a 2e^(-) pathway is thermodynamically more difficult than to O_(2)via a 4e^(-)pathway.Herein,with a series of BiVO_(4)-based photoanodes,the decisive factors determining the PEC activity and selectivity are elucidated,combining a comprehensive experimental and theoretical investigations.It is discovered that the ZnO/BiVO_(4)photoanode(ZnO/BVO)forms a Type-Ⅱheterojunction in energy level alignment.The accelerated photogenerated charge separation/transfer dynamics generates denser surface holes and higher surface photovoltage.Therefore,the activity of water oxidation reaction is promoted.The selectivity of PEC-WO to H_(2)O_(2)is found to be potential-dependent,i.e.,at the lower potentials(PEC-dominated),surface hole density determines the selectivity;and at the higher potentials(electrochemical-dominated),surface reaction barriers govern the selectivity.For the ZnO/BVO heterojunction photoanode,the higher surface hole density facilitates the generation of OH·and the subsequent OH·/OH·coupling to form H_(2)O_(2),thus rising up with potentials;at the higher potentials,the 2-electron pathway barrier over ZnO/BVO surface is lower than over BVO surface,which benefits from the electronic structure regulation by the underlying ZnO alleviating the over-strong adsorption of^(*)OH on BVO,thus,the two-electron pathway to produce H_(2)O_(2)is more favored than on BVO surface.This work highlights the crucial role of band energy structure of semiconductors on both PEC reaction activity and selectivity,and the knowledge gained is expected to be extended to other photoeletrochemical reactions.
基金supported by the National Key Research and Development Program of China(No.2021YFA1500601)the National Natural Science Foundation of China(Nos.22322306 and 22288201)+3 种基金the Chinese Academy of Sciences(Nos.YSBR007,XDB0970000)the Key Research Project of Shaanxi Provincial Science and Technology Department(No.2023-YBNY-158)the Xi’an Science and Technology Project(No.22NYYF016)the 111 Project。
文摘The oxygen evolution reaction(OER)is the bottleneck in the overall photocatalytic splitting of water.The active sites(terminal titanium or bridging oxygen)and active species(molecular or dissociative water)of the initial step of the photocatalyzed OER on the prototypical photocatalyst TiO_(2),remain debatable.Herein,the photocatalytic chemistry of monolayer water on oxygen-pretreated TiO_(2)(110)(o-TiO_(2)(110))and reduced TiO_(2)(110)(r-TiO_(2)(110))surfaces initiated by 400 nm light illumination was investigated by time-dependent two-photon photoemission spectroscopy(TD-2PPE).The photoinduced reduction of the H_(2)O/o-TiO_(2)(110)interface rather than the H2O/r-TiO_(2)(110)interface was detected by TD-2PPE.The difference in 2PPE originated from the presence of the terminal hydroxyl anions(OHt^(-))on H_(2)O/o-TiO_(2)(110),as identified by X-ray photoelectron spectroscopy and temperature-programmed desorption.Therefore,the evolution of the electronic structure of H_(2)O/o-TiO_(2)(110)was attributed to the photocatalyzed oxidation of the terminal hydroxyl anions,which most likely formed gaseous·OH radicals,reducing the interface.This work suggested that the oxidation of hydroxyl anions on top of the terminal titanium ions on TiO_(2),which were excluded previously in solution,need to be considered in the mechanistic studies of the photocatalyzed OER.
