CO_(2)hydrogenation to value-added light olefins(C_(2-4)=)is crucial for the utilization and cycling of global carbon resource.Moderate CO_(2)activation and carbon chain growth ability are key factors for iron-based c...CO_(2)hydrogenation to value-added light olefins(C_(2-4)=)is crucial for the utilization and cycling of global carbon resource.Moderate CO_(2)activation and carbon chain growth ability are key factors for iron-based catalysts for efficient CO_(2)conversion to target C_(2-4)=products.The electronic interaction and confinement effect of electron-deficient graphene inner surface on the active phase are effective to improve surface chemical properties and enhance the catalytic performance.Here,we report a core-shell FeCo alloy catalyst with graphene layers confinement prepared by a simple sol-gel method.The electron transfer from Fe species to curved graphene inner surface modifies the surface electronic structure of the active phaseχ-(Fe_(x)Co_(1-x))_(5)C_(2)and improves CO_(2)adsorption capacity,enhancing the efficient conversion of CO_(2)and moderate C-C coupling.Therefore,the catalyst FeCoK@C exhibits C_(2-4)=selectivity of 33.0%while maintaining high CO_(2)conversion of 52.0%.The high stability without obvious deactivation for over 100 h and unprecedented C_(2-4)=space time yield(STY)up to 52.9 mmolCO_(2)·g^(-1)·h^(-1)demonstrate its potential for practical application.This work provides an efficient strategy for the development of high-performance CO_(2)hydrogenation catalysts.展开更多
The unique properties of TiO_(2)-sulfur(TiO_(2)-S)modified graphene nanocomposite electrode(GPE/TiO_(2)-S)in the electrochemical sensing of formaldehyde compound has been evaluated.We prepared TiO_(2)-S by hydrotherma...The unique properties of TiO_(2)-sulfur(TiO_(2)-S)modified graphene nanocomposite electrode(GPE/TiO_(2)-S)in the electrochemical sensing of formaldehyde compound has been evaluated.We prepared TiO_(2)-S by hydrothermal method and modified the graphene nanocomposite electrode by applying electrochemical cyclic voltammetry(CV)approach.The TiO_(2)-S nanocomposite was characterized by X-ray diffraction(XRD),while the GPE/TiO_(2)-S was examined by scanning electron microscopy(FESEM)and X-Ray fluorosense(XRF)techniques.TiO_(2)-S has a grain size of 19.32 nm.The surface morphology of the GPE/TiO_(2)-S nanocomposite shows a good,intact,and tightly porous structure with TiO_(2)-S covers the graphene surface.The content of optimized GPE/TiO_(2)-S electrodes is 41.5%of graphene,37.8%of TiO_(2),and 12.4%of sulfur that was prepared by mixing 1 g of TiO_(2)-S with 0.5 g of graphene and 0.3 mL paraffin.The GPE/TiO_(2)-S electrode produces a high anodic current(I_(pa))of 800μA and a high cathodic current(I_(pc))of-600μA at a scan rate of 0.1 V·s^(-1)using an electrolyte0.01 mol·L^(-1)K_3[Fe(CN)_6]solution containing 150 mg·L^(-1)formaldehyde.The limit of detection can reach as low as 9.7 mg·L^(-1)with stability with Horwitz ratio value as low as 0.397.The composite electrode also exhibits excellent slectivity properties by showing clear formaldehyde sugnal in the presence of high concentration of interfering agent.GPE/TiO_(2)-S electrode should find potential application of formaldehyde detection in food industries.展开更多
Optical polarizers,which allow the transmission of specific polarization states,are essential components in modern optical systems.Here,we experimentally demonstrate integrated photonic polarizers incorporating reduce...Optical polarizers,which allow the transmission of specific polarization states,are essential components in modern optical systems.Here,we experimentally demonstrate integrated photonic polarizers incorporating reduced graphene oxide(rGO)films.2D graphene oxide(GO)films are integrated onto silicon waveguides and microring resonators(MRRs)with precise control over their thicknesses and sizes,followed by GO reduction via two different methods including uniform thermal reduction and localized photothermal reduction.We measure devices with various lengths,thicknesses,and reduction degrees of GO films.The results show that the devices with rGO exhibit better performance than those with GO,achieving a polarization-dependent loss of~47 dB and a polarization extinction ratio of~16 dB for the hybrid waveguides and MRRs with rGO,respectively.By fitting the experimental results with theory,it is found that rGO exhibits more significant anisotropy in loss,with an anisotropy ratio over 4 times that of GO.In addition,rGO shows higher thermal stability and greater robustness to photothermal reduction than GO.These results highlight the strong potential of rGO films for implementing high-performance polarization selective devices in integrated photonic platforms.展开更多
Manipulating catalyst structures to control product selectivity while maintaining high activity presents a considerable challenge in CO_(2)hydrogenation.Combining density functional theory calculations and microkineti...Manipulating catalyst structures to control product selectivity while maintaining high activity presents a considerable challenge in CO_(2)hydrogenation.Combining density functional theory calculations and microkinetic analysis,we proposed that graphene-supported isolated Pt atoms(Pt1/graphene)and Pt_(2)dimers(Pt_(2)/graphene)exhibited distinct selectivity in CO_(2)hydrogenation.Pt_(1)/graphene facilitated the conversion of CO_(2)into formic acid,whereas Pt_(2)/graphene favored methanol generation.The variation in product selectivity arose from the synergistic interaction of Pt_(2)dimers,which facilitated the migration of H atoms between two Pt atoms and promoted the transformation from*COOH intermediates to*C(OH)_(2)intermediates,altering the reaction pathways compared to isolated Pt atoms.Additionally,an analysis of the catalytic activities of three Pt_(1)/graphene and three Pt_(2)/graphene structures revealed that the turnover frequencies for formic acid generation on Pt_(1ii)/graphene and methanol generation on Pt_(2i)/graphene were as high as 744.48 h-1and 789.48 h^(-1),respectively.These values rivaled or even surpassed those previously reported in the literature under identical conditions.This study provides valuable insights into optimizing catalyst structures to achieve desired products in CO_(2)hydrogenation.展开更多
Charge-neutral method(CNM)is extensively used in investigating the performance of catalysts and the mechanism of N_(2)electrochemical reduction(NRR).However,disparities remain between the predicted potentials required...Charge-neutral method(CNM)is extensively used in investigating the performance of catalysts and the mechanism of N_(2)electrochemical reduction(NRR).However,disparities remain between the predicted potentials required for NRR by the CNM methods and those observed experimentally,as the CNM method neglects the charge effect from the electrode potential.To address this issue,we employed the constant electrode potential(CEP)method to screen atomic transition metal-N-graphene(M_(1)/N-graphene)as NRR electrocatalysts and systematically investigated the underlying catalytic mechanism.Among eight types of M_(1)/N-graphene(M_(1)=Mo,W,Fe,Re,Ni,Co,V,Cr),W_(1)/N-graphene emerges as the most promising NRR electrocatalyst with a limiting potential as low as−0.13 V.Additionally,the W_(1)/N-graphene system consistently maintains a positive charge during the reaction due to its Fermi level being higher than that of the electrode.These results better match with the actual circumstances compared to those calculated by conventional CNM method.Thus,our work not only develops a promising electrocatalyst for NRR but also deepens the understanding of the intrinsic electrocatalytic mechanism.展开更多
Graphene has enormous potential to capture CO_(2)due to its unique properties and cost-effectiveness.However,graphene-based adsorbents have drawbacks of lower CO_(2)adsorption capacity and poor selectivity.This work d...Graphene has enormous potential to capture CO_(2)due to its unique properties and cost-effectiveness.However,graphene-based adsorbents have drawbacks of lower CO_(2)adsorption capacity and poor selectivity.This work demonstrates a one-step rapid and sustainable N_(2)/H_(2)plasma treatment process to prepare graphene-based sorbent material with enhanced CO_(2)adsorption performance.Plasma treatment directly enriches amine species,increases surface area,and improves textural properties.The CO_(2)adsorption capacity increases from 1.6 to 3.3 mmol/g for capturing flue gas,and from 0.14 to 1.3 mmol/g for direct air capture (DAC).Importantly,the electrothermal property of the plasma-modified aerogels has been significantly improved,resulting in faster heating rates and significantly reducing energy consumption compared to conventional external heating for regeneration of sorbents.Modified aerogels display improved selectivity of 42 and 87 after plasma modification for 5 and 10 min,respectively.The plasma-treated aerogels display minimal loss between 17%and 19% in capacity after 40 adsorption/desorption cycles,rendering excellent stability.The N_(2)/H_(2)plasma treatment of adsorbent materials would lower energy expenses and prevent negative effects on the global economy caused by climate change.展开更多
The production of hydrogen peroxide(H_(2)O_(2))via artificial photosynthesis using single-atom semiconductor photocatalysts represents a promising green and sustainable technology.However,its efficiency is still limit...The production of hydrogen peroxide(H_(2)O_(2))via artificial photosynthesis using single-atom semiconductor photocatalysts represents a promising green and sustainable technology.However,its efficiency is still limited by sluggish water oxidation kinetics,poor photogenerated charge separation,and insufficient O_(2)adsorption and activation capabilities.Herein,uniformly dispersed single-atom catalysts(SACs)with a Co-N_(4)coordination structure have been synthesized by thermally transforming cobalt phthalocyanine(CoPc)assemblies pre-anchored on phosphate functionalized reduced graphene oxide(Co@rGO-P),and then used to construct heterojunctions with perylenetetracarboxylic acid(PTA)nanosheets for photocatalytic H_(2)O_(2)production by an in-situ growth method.The optimized Co@rGO-P/PTA achieved an H_(2)O_(2)production rate of 1.4 mmol g^(-1)h^(-1)in pure water,with a 12.9-fold enhancement compared to pristine PTA nanosheets exhibiting competitive photoactivity among reported perylene-based materials.Femtosecond transient absorption spectra,in-situ diffuse reflectance infrared Fourier transform spectra and theoretical calculations reveal that the exceptional performance is attributed to the enhanced electron transfer from PTA to rGO via the phosphate bridge and then to the Co-N_(4),and to the promoted O_(2)adsorption and activation at Co-N_(4)active sites.This work provides a feasible and effective strategy for designing highly efficient single-atom semiconductor heterojunction photocatalysts for H_(2)O_(2)production.展开更多
Conversion-type anode materials are highly desirable for Na-ion batteries(NIBs)due to their high theoretical capacity.Nevertheless,the active materials undergo severe expansion and pulverization during the sodiation,r...Conversion-type anode materials are highly desirable for Na-ion batteries(NIBs)due to their high theoretical capacity.Nevertheless,the active materials undergo severe expansion and pulverization during the sodiation,resulting in inferior cycling stability.Herein,a self-supporting three-dimensional(3D)graphene sponge decorated with Fe_(2)O_(3)nanocubes(rGO@Fe_(2)O_(3))is constructed.Specifically,the 3D graphene sponge with resilience and high porosity benefits to accommodate the volume expansion of the Fe_(2)O_(3)nanocubes and facilitates the rapid electrons/ions transport,enabling spatial confinement to achieve outstanding results.Besides,the free-standing rGO@Fe_(2)O_(3)can be directly used as an electrode without additional binders and conductive additives,which helps to obtain a higher energy density.Based on the total mass of the rGO@Fe_(2)O_(3)material,the rGO@Fe_(2)O_(3)anode presents a specific capacity of 859 mAh/g at 0.1 A/g.It also delivers an impressive cycling performance(327 mAh/g after 2000 cycles at 1 A/g)and a superior rate capacity(162mAh/g at 20 A/g).The coin-type Na_(3)V_(2)(PO_(4))_(3)@C//rGO@Fe_(2)O_(3)NIB exhibits an energy density of 265.3Wh/kg.This unique 3D ionic/electronic conductive network may provide new strategies to design advanced conversion-type anode materials for high-performance NIBs.展开更多
In this study,the holey graphene was prepared by microwave-assisted chemical etching.The three-dimensional(3D)holey graphene hydrogel was obtained through hydrothermal self-assembly method,followed by the introduction...In this study,the holey graphene was prepared by microwave-assisted chemical etching.The three-dimensional(3D)holey graphene hydrogel was obtained through hydrothermal self-assembly method,followed by the introduction of FeCo_(2)S_(4)particles.The resulting holey graphene hydrogel,characterized by high specific surface area and abundant pores combined with FeCo_(2)S_(4)with high pseudocapacitance by interfacial interaction,shortened the mass transport path and enhanced the specific capacitance.The findings reveal that the holey graphene hydrogel/FeCo_(2)S_(4)(FeCo_(2)S_(4)/HGH)composite exhibits high specific capacitance and impressive rate capability(413.4 F·g^(-1)at 1 A·g^(-1),300.4 F·g^(-1)at 6 A·g^(-1)).The symmetric supercapacitor operated within a stable potential window of 0.1-1.6 V,achieving specific capacitance of 127.5 F·g^(-1)at 1 A·g^(-1),and can deliver 37.1 Wh·kg^(-1)at a power density of 1499 W·kg^(-1).Besides,under the current density of 3 A·g^(-1),the supercapacitor retained 90.8%of its capacitance after 5000 cycles,demonstrating exceptional cycle stability.This study presents an efficient method for fabricating advanced integrated supercapacitors electrodes with enhanced energy density.展开更多
Low-cost Fe-based disordered rock salt(DRX)Li_(2)FeTiO_(4)is capable of providing high capacity(295 mA h g^(-1))by redox activity of cations(Fe^(2+)/Fe^(4+)and Ti^(3+)/Ti^(4+))and anionic oxygen.However,DRX structures...Low-cost Fe-based disordered rock salt(DRX)Li_(2)FeTiO_(4)is capable of providing high capacity(295 mA h g^(-1))by redox activity of cations(Fe^(2+)/Fe^(4+)and Ti^(3+)/Ti^(4+))and anionic oxygen.However,DRX structures lack transport channels for ions and electrons,resulting in sluggish kinetics,poor electrochemical activity,and cyclability.Herein,graphene conductive carbon network permeated Li_(2)FeTiO_(4)(LFT/C/G)nanofibers are successfully prepared by a facile sol-gel assisted electrospinning method.Ultrafine Li_(2)FeTiO_(4)nanoparticles(2 nm)and one-dimensional(1D)structure provide abu ndant active sites and unobstructed diffu sion channels,accelerating ion diffusion.In addition,introducing graphene reduces the band gap and Li^(+)diffusion barrier and improves the dynamic properties of Li_(2)FeTiO_(4),thus achieving a relatively mild interfacial reaction and reversible redox reaction.As expected,the LFT/C/1.0G cathode delivers a remarkable discharge capacity(238.5 mA h g^(-1)),high energy density(508.8 Wh kg^(-1)),and excellent rate capability(51.2 mA hg^(-1)at 1.0 A g^(-1)).Besides,the LFT/C/1.0G anode also displays a high capacity(514.5 mA h g^(-1)at 500 mA g^(-1))and a remarkable rate capability(243.9 mA h g^(-1)at 8 A g^(-1)).Moreover,the full batteries based on the LFT/C/1.0G symmetric electrode demonstrate a reversible capacity of 117.0 mA h g^(-1)after 100 cycles at 50 mA g^(-1).This study presents useful insights into developing cost-effective DRX cathodes with durable and fast lithium storage.展开更多
ZrO2/Graphene nanocomposites are fabricated from graphene oxide by one-step, green, facile and low-cost SCCO2 method. The as-prepared nanocomposites are characterized by means of X-ray photoelectron, transmission elec...ZrO2/Graphene nanocomposites are fabricated from graphene oxide by one-step, green, facile and low-cost SCCO2 method. The as-prepared nanocomposites are characterized by means of X-ray photoelectron, transmission electron microscopy and catalytic chemiluminescence measurement. The ZrO2 nanoparticles with size of several nanometers are uniformly coated on the graphene surface. The chemiluminescence characteristic to ethanol of the as-prepared nanocomposite paper is also investigated. The nanocomposite paper obtained displays high catalytic chemiluminescence sensitivity and highly selectivity to the ethanol gas. This study provides a facile, green and low-cost route to prepare nanoscopic gas sensing devices with application in safe protection, food fermentation, medical process and traffic safe.展开更多
The synthesis of a perpendicular growth structure of MoS_(2)nanosheets on graphene for efficient sodium storage is challenging yet ideal due to the benefits of open ion diffusion channels and high electronic conductiv...The synthesis of a perpendicular growth structure of MoS_(2)nanosheets on graphene for efficient sodium storage is challenging yet ideal due to the benefits of open ion diffusion channels and high electronic conductivity.In this study,we have successfully fabricated a novel structure of vertical MoS_(2)nanosheets on graphene,with ZnS nanoparticles serving as bonding points(MoS_(2)/ZnS/G),through a facile hydrothermal method.During the synthesis process,Zn^(2+)not only acts as a landing site for the vertical growth of MoS_(2)nanosheets but also triggers the formation of a defect-rich structure in the final samples.This unique architecture of MoS_(2)/ZnS/G effectively combines the advantages of a vertically aligned geometry and a defectrich structure for energy storage.The resulting structure displays shortened transport paths for electrons/ions,enhanced conductivity,improved structural integrity,and an increased number of active sites for promising electrochemical performance.As expected,when used as anode for sodium-ion batteries,the as-synthesize d MoS_(2)/ZnS/G exhibits excellent rate capability(high capacity of 298 mAh·g^(-1)at 5 A·g^(-1))and good cycling stability(a capacity decay of 0.056%per cycle after 500 cycles at 1 A·g^(-1)).According to the kinetic investigations,the electrochemical process of the MoS_(2)/ZnS/G sample is primarily governe d by a pseudocapacitive behavior,which enhances the charge/discharge kinetics and allows the MoS_(2)/ZnS/G structure to remain intact during cycling.展开更多
Manganese ferrite(MnFe_(2)O_(4))has the advantages of simple preparation,high resistivity,and high crystal symmetry.Herein,we have developed an electrochemical sensor utilizing graphene and MnFe_(2)O_(4) nanocomposite...Manganese ferrite(MnFe_(2)O_(4))has the advantages of simple preparation,high resistivity,and high crystal symmetry.Herein,we have developed an electrochemical sensor utilizing graphene and MnFe_(2)O_(4) nanocomposites modified glassy carbon electrode(GCE),which is very efficient and sensitive to detect bisphenol A(BPA).MnFe_(2)O_(4)/graphene(GR)was synthesized by immobilizing the MnFe_(2)O_(4) microspheres on the graphene nanosheets via a simple one-pot solvothermal method.The morphology and structure of the MnFe_(2)O_(4)/GR nanocomposite have been characterized through scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).In addition,electrochemical properties of the modified materials are comparably explored by means of cyclic voltammetry(CV),electrochemical impedance spectroscopy(EIS)and differential pulse voltammetry(DPV).Under the optimal conditions,the proposed electrochemical sensor for the detection of BPA has a linear range of 0.8-400μmol/L and a detection limit of 0.0235μmol/L(S/N=3)with high sensitivity,good selectivity and high stability.In addition,the proposed sensor was used to measure the content of BPA in real water samples with a recovery rate of 97.94%-104.56%.At present,the synthesis of MnFe_(2)O_(4)/GR provides more opportunities for the electrochemical detection of BPA in practical applications.展开更多
A novel approach was developed to fabricate a label-free electrochemical aptasensor for specific detection of mercury ions(Hg^(2+)).This involved modifying polylysine(PLL)-coated black phosphorus-porous graphene(BP-PG...A novel approach was developed to fabricate a label-free electrochemical aptasensor for specific detection of mercury ions(Hg^(2+)).This involved modifying polylysine(PLL)-coated black phosphorus-porous graphene(BP-PG)nanocomposites(PLL/BP-PG)onto the surface of glassy carbon electrodes(GCE),which were further modified with gold nanoparticles(AuNPs)to combine with a thiolated aptamer(Apt)capable of specifically recognizing Hg^(2+).BP-PG was synthesized using the solvothermal method and covalently bonded to form BP-PG nanosheets,resulting in significant enhanced electrochemical properties of the PLL/BP-PG composite.Furthermore,the PLL/BP-PG composite was improved environmental stability of BP and provided a considerable quantity of-NH_(2)for bonding to Au NPs firmly by assembling.The physical properties and electrochemical behavior of the substrate materials were investigated using various characterization techniques,and analytical parameters were optimized.It is shown that,the Apt/AuNPs/PLL/BP-PG/GCE had a linear response(R~2=0.999)with good selectivity and high sensitivity over the Hg^(2+)range of 1-10,000 nmol/L.The proposed sensor has a detection limit of 0.045 nmol/L and can be employed for detecting of Hg^(2+).It also obtained satisfying results in river water,soil and vegetable samples.展开更多
Exclusive responsiveness to ultraviolet light (~3.2 eV) and high photogenerated charge recombination rate are the two primary drawbacks of pure TiO_(2). We combined N-doped graphene quantum dots (N-GQDs), morphology r...Exclusive responsiveness to ultraviolet light (~3.2 eV) and high photogenerated charge recombination rate are the two primary drawbacks of pure TiO_(2). We combined N-doped graphene quantum dots (N-GQDs), morphology regulation, and heterojunction construction strategies to synthesize N-GQD/N-doped TiO_(2)/P-doped porous hollow g-C_(3)N_(4) nanotube (PCN) composite photocatalysts (denoted as G-TPCN). The optimal sample (G-TPCN doped with 0.1wt% N-GQD, denoted as 0.1% G-TPCN) exhibits significantly enhanced photoabsorption, which is attributed to the change in bandgap caused by elemental doping (P and N), the improved light-harvesting resulting from the tube structure, and the upconversion effect of N-GQDs. In addition, the internal charge separation and transfer capability of0.1% G-TPCN are dramatically boosted, and its carrier concentration is 3.7, 2.3, and 1.9 times that of N-TiO_(2), PCN, and N-TiO_(2)/PCN(TPCN-1), respectively. This phenomenon is attributed to the formation of Z-scheme heterojunction between N-TiO_(2) and PCNs, the excellent electron conduction ability of N-GQDs, and the short transfer distance caused by the porous nanotube structure. Compared with those of N-TiO_(2), PCNs, and TPCN-1, the H2 production activity of 0.1%G-TPCN under visible light is enhanced by 12.4, 2.3, and 1.4times, respectively, and its ciprofloxacin (CIP) degradation rate is increased by 7.9, 5.7, and 2.9 times, respectively. The optimized performance benefits from excellent photoresponsiveness and improved carrier separation and migration efficiencies. Finally, the photocatalytic mechanism of 0.1% G-TPCN and five possible degradation pathways of CIP are proposed. This study clarifies the mechanism of multiple modification strategies to synergistically improve the photocatalytic performance of 0.1% G-TPCN and provides a potential strategy for rationally designing novel photocatalysts for environmental remediation and solar energy conversion.展开更多
Developing innovative catalysts continues to be a pivotal interest within the heterogeneous catalysis area.The carbonaceous material ND@G,featuring a sp^(2)/sp^(3)hybrid architecture,comprises a nanodiamond(ND)core st...Developing innovative catalysts continues to be a pivotal interest within the heterogeneous catalysis area.The carbonaceous material ND@G,featuring a sp^(2)/sp^(3)hybrid architecture,comprises a nanodiamond(ND)core structure encased within an ultrathin graphitic nanoshell(G),and has been widely exploited as a metal-free catalyst or a support for metal catalyst.Its unique curved zero-dimensional structure/surface and tunable defective surface characteristics endow it with outstanding performance in different heterogeneous catalytic systems.The present review summarized the construction of the diverse types of ND@G and a wide-ranging valorization of structure-activity relation with its catalytic mechanism in various reactions.The recent advancements in the impact of active sites’architecture and the interaction between metal and support(preventing the as-formed metal species migration and agglomeration based on ND@G)on the catalytic performance of supported metal catalysts are particularly highlighted.The current challenges and outlooks/opportunities confronted by ND@G materials in catalysis are prospected by virtue of its fundamental physicochemical characterizations and potential catalytic estimation.This in-depth analysis seeks to pave the way for effective utilizing the ND@G in catalytic processes.Based on our knowledge,we also identify the challenges along with this area and offer some perspectives on how to overcome them.展开更多
A hierarchical reduced graphene oxide-MnO_(2)@polypyrrole coaxial nanotube composite hydrogel was prepared via oxidative polymerization of pyrrole in the presence of MnO_(2)nanotubes,followed by the hydrothermal treat...A hierarchical reduced graphene oxide-MnO_(2)@polypyrrole coaxial nanotube composite hydrogel was prepared via oxidative polymerization of pyrrole in the presence of MnO_(2)nanotubes,followed by the hydrothermal treatment of graphene oxide and MnO_(2)@polypyrrole coaxial nanotubes.The stable composite hydrogel with a hierarchical network was composed of one-dimensional MnO_(2)@polypyrrole coaxial nanotube and two-dimensional graphene nanosheet and characterized by scanning electron microscope,Fourier transform infrared spectroscopy,X-ray diffraction,Brunauer-Emmett-Teller surface,and X-ray photoelectron spectroscopy measurements.The composite hydrogel can be used as an efficient adsorbent for Cr(Ⅵ)removal due to the synergistic interaction between graphene and MnO_(2)@polypyrrole and the hierarchical structure of the hydrogel.Moreover,the composite hydrogel is easily separated because of its stable monolith,and it is reusable(76.8%of removal ability remaining after five adsorption-desorption cycles).The simple fabrication and cost-effective separation process together with the excellent absorption performance endow the composite hydrogel with great potential for practical wastewater treatment.展开更多
For the application of carbon capture by membrane process,it is crucial to develop a highly permeable CO_(2)-selective membrane.In this work,we reported an ultra-thin polyether-block-amide(Pebax)mixedmatrix membranes(...For the application of carbon capture by membrane process,it is crucial to develop a highly permeable CO_(2)-selective membrane.In this work,we reported an ultra-thin polyether-block-amide(Pebax)mixedmatrix membranes(MMMs)incorporated by graphene oxide(GO),in which the interlayer channels were regulated to optimize the CO_(2)/N_(2) separation performance.Various membrane preparation conditions were systematically investigated on the influence of the membrane structure and separation performance,including the lateral size of GO nanosheets,GO loading,thermal reduction temperature,and time.The results demonstrated that the precisely regulated interlayer channel of GO nanosheets can rapidly provide CO_(2)-selective transport channels due to the synergetic effects of size sieving and preferential adsorption.The GO/Pebax ultra-thin MMMs exhibited CO_(2)/N_(2) selectivity of 72 and CO_(2) permeance of 400 GPU(1 GPU=106 cm^(3)(STP)·cm^(2)·s^(-1)·cmHg^(-1)),providing a promising candidate for CO_(2) capture.展开更多
文摘CO_(2)hydrogenation to value-added light olefins(C_(2-4)=)is crucial for the utilization and cycling of global carbon resource.Moderate CO_(2)activation and carbon chain growth ability are key factors for iron-based catalysts for efficient CO_(2)conversion to target C_(2-4)=products.The electronic interaction and confinement effect of electron-deficient graphene inner surface on the active phase are effective to improve surface chemical properties and enhance the catalytic performance.Here,we report a core-shell FeCo alloy catalyst with graphene layers confinement prepared by a simple sol-gel method.The electron transfer from Fe species to curved graphene inner surface modifies the surface electronic structure of the active phaseχ-(Fe_(x)Co_(1-x))_(5)C_(2)and improves CO_(2)adsorption capacity,enhancing the efficient conversion of CO_(2)and moderate C-C coupling.Therefore,the catalyst FeCoK@C exhibits C_(2-4)=selectivity of 33.0%while maintaining high CO_(2)conversion of 52.0%.The high stability without obvious deactivation for over 100 h and unprecedented C_(2-4)=space time yield(STY)up to 52.9 mmolCO_(2)·g^(-1)·h^(-1)demonstrate its potential for practical application.This work provides an efficient strategy for the development of high-performance CO_(2)hydrogenation catalysts.
基金the financial support from the Ministry of Education,Culture,Research and Technology of the Republic of Indonesia under the Applied Research award(DIPA023.17.1.690523/2023)the World Class Professor award grant 2023。
文摘The unique properties of TiO_(2)-sulfur(TiO_(2)-S)modified graphene nanocomposite electrode(GPE/TiO_(2)-S)in the electrochemical sensing of formaldehyde compound has been evaluated.We prepared TiO_(2)-S by hydrothermal method and modified the graphene nanocomposite electrode by applying electrochemical cyclic voltammetry(CV)approach.The TiO_(2)-S nanocomposite was characterized by X-ray diffraction(XRD),while the GPE/TiO_(2)-S was examined by scanning electron microscopy(FESEM)and X-Ray fluorosense(XRF)techniques.TiO_(2)-S has a grain size of 19.32 nm.The surface morphology of the GPE/TiO_(2)-S nanocomposite shows a good,intact,and tightly porous structure with TiO_(2)-S covers the graphene surface.The content of optimized GPE/TiO_(2)-S electrodes is 41.5%of graphene,37.8%of TiO_(2),and 12.4%of sulfur that was prepared by mixing 1 g of TiO_(2)-S with 0.5 g of graphene and 0.3 mL paraffin.The GPE/TiO_(2)-S electrode produces a high anodic current(I_(pa))of 800μA and a high cathodic current(I_(pc))of-600μA at a scan rate of 0.1 V·s^(-1)using an electrolyte0.01 mol·L^(-1)K_3[Fe(CN)_6]solution containing 150 mg·L^(-1)formaldehyde.The limit of detection can reach as low as 9.7 mg·L^(-1)with stability with Horwitz ratio value as low as 0.397.The composite electrode also exhibits excellent slectivity properties by showing clear formaldehyde sugnal in the presence of high concentration of interfering agent.GPE/TiO_(2)-S electrode should find potential application of formaldehyde detection in food industries.
基金supported by the Australian Research Council Centre of Excellence Project in Optical Microcombs for Breakthrough Science(No.CE230100006)the Australian Research Council Discovery Projects Programs(Nos.P190103186 and FT210100806)+4 种基金Linkage Program(Nos.LP210200345 and LP210100467)the Swinburne ECR-SUPRA program,the Industrial Transformation Training Centres scheme(No.IC180100005)the National Natural Science Foundation of China(No.12404375)the Beijing Natural Science Foundation(No.Z180007)the Innovation Program for Quantum Science and Technology(No.2021ZD0300703).
文摘Optical polarizers,which allow the transmission of specific polarization states,are essential components in modern optical systems.Here,we experimentally demonstrate integrated photonic polarizers incorporating reduced graphene oxide(rGO)films.2D graphene oxide(GO)films are integrated onto silicon waveguides and microring resonators(MRRs)with precise control over their thicknesses and sizes,followed by GO reduction via two different methods including uniform thermal reduction and localized photothermal reduction.We measure devices with various lengths,thicknesses,and reduction degrees of GO films.The results show that the devices with rGO exhibit better performance than those with GO,achieving a polarization-dependent loss of~47 dB and a polarization extinction ratio of~16 dB for the hybrid waveguides and MRRs with rGO,respectively.By fitting the experimental results with theory,it is found that rGO exhibits more significant anisotropy in loss,with an anisotropy ratio over 4 times that of GO.In addition,rGO shows higher thermal stability and greater robustness to photothermal reduction than GO.These results highlight the strong potential of rGO films for implementing high-performance polarization selective devices in integrated photonic platforms.
基金supported by the National Key Research and Development Program(No.2022YFA1505800)the National Natural Science Foundation of China(No.22373092)+5 种基金CAS Project for Young Scientists in Basic Research(No.YSBR-051)China Association for Science and Technology(No.YESS20200031)the Start-up Funding of Central South University(No.502045005)Industry-University-Research Cooperation Projects with Zhejiang NHU Co.,Ltd.Ningbo Fengcheng Advanced Energy Materials Research Institutesupported by USTC Tang Scholarship。
文摘Manipulating catalyst structures to control product selectivity while maintaining high activity presents a considerable challenge in CO_(2)hydrogenation.Combining density functional theory calculations and microkinetic analysis,we proposed that graphene-supported isolated Pt atoms(Pt1/graphene)and Pt_(2)dimers(Pt_(2)/graphene)exhibited distinct selectivity in CO_(2)hydrogenation.Pt_(1)/graphene facilitated the conversion of CO_(2)into formic acid,whereas Pt_(2)/graphene favored methanol generation.The variation in product selectivity arose from the synergistic interaction of Pt_(2)dimers,which facilitated the migration of H atoms between two Pt atoms and promoted the transformation from*COOH intermediates to*C(OH)_(2)intermediates,altering the reaction pathways compared to isolated Pt atoms.Additionally,an analysis of the catalytic activities of three Pt_(1)/graphene and three Pt_(2)/graphene structures revealed that the turnover frequencies for formic acid generation on Pt_(1ii)/graphene and methanol generation on Pt_(2i)/graphene were as high as 744.48 h-1and 789.48 h^(-1),respectively.These values rivaled or even surpassed those previously reported in the literature under identical conditions.This study provides valuable insights into optimizing catalyst structures to achieve desired products in CO_(2)hydrogenation.
基金Natural Science Foundation of Guangdong Province(No.2024A1515011094(C.Q Sun))National Natural Science Foundation of China(Nos.12304243(H.X.Fang),12150100(B.Wang))is gratefully acknowledged。
文摘Charge-neutral method(CNM)is extensively used in investigating the performance of catalysts and the mechanism of N_(2)electrochemical reduction(NRR).However,disparities remain between the predicted potentials required for NRR by the CNM methods and those observed experimentally,as the CNM method neglects the charge effect from the electrode potential.To address this issue,we employed the constant electrode potential(CEP)method to screen atomic transition metal-N-graphene(M_(1)/N-graphene)as NRR electrocatalysts and systematically investigated the underlying catalytic mechanism.Among eight types of M_(1)/N-graphene(M_(1)=Mo,W,Fe,Re,Ni,Co,V,Cr),W_(1)/N-graphene emerges as the most promising NRR electrocatalyst with a limiting potential as low as−0.13 V.Additionally,the W_(1)/N-graphene system consistently maintains a positive charge during the reaction due to its Fermi level being higher than that of the electrode.These results better match with the actual circumstances compared to those calculated by conventional CNM method.Thus,our work not only develops a promising electrocatalyst for NRR but also deepens the understanding of the intrinsic electrocatalytic mechanism.
基金Guangzhou (China) government postdoctoral program for providing financial support to conduct this worksupport from the National Natural Science Foundation of China (No. 72140008)funding from the European Union’s Horizon 2020 Research and Innovation program under grant agreement No. 101022484。
文摘Graphene has enormous potential to capture CO_(2)due to its unique properties and cost-effectiveness.However,graphene-based adsorbents have drawbacks of lower CO_(2)adsorption capacity and poor selectivity.This work demonstrates a one-step rapid and sustainable N_(2)/H_(2)plasma treatment process to prepare graphene-based sorbent material with enhanced CO_(2)adsorption performance.Plasma treatment directly enriches amine species,increases surface area,and improves textural properties.The CO_(2)adsorption capacity increases from 1.6 to 3.3 mmol/g for capturing flue gas,and from 0.14 to 1.3 mmol/g for direct air capture (DAC).Importantly,the electrothermal property of the plasma-modified aerogels has been significantly improved,resulting in faster heating rates and significantly reducing energy consumption compared to conventional external heating for regeneration of sorbents.Modified aerogels display improved selectivity of 42 and 87 after plasma modification for 5 and 10 min,respectively.The plasma-treated aerogels display minimal loss between 17%and 19% in capacity after 40 adsorption/desorption cycles,rendering excellent stability.The N_(2)/H_(2)plasma treatment of adsorbent materials would lower energy expenses and prevent negative effects on the global economy caused by climate change.
文摘The production of hydrogen peroxide(H_(2)O_(2))via artificial photosynthesis using single-atom semiconductor photocatalysts represents a promising green and sustainable technology.However,its efficiency is still limited by sluggish water oxidation kinetics,poor photogenerated charge separation,and insufficient O_(2)adsorption and activation capabilities.Herein,uniformly dispersed single-atom catalysts(SACs)with a Co-N_(4)coordination structure have been synthesized by thermally transforming cobalt phthalocyanine(CoPc)assemblies pre-anchored on phosphate functionalized reduced graphene oxide(Co@rGO-P),and then used to construct heterojunctions with perylenetetracarboxylic acid(PTA)nanosheets for photocatalytic H_(2)O_(2)production by an in-situ growth method.The optimized Co@rGO-P/PTA achieved an H_(2)O_(2)production rate of 1.4 mmol g^(-1)h^(-1)in pure water,with a 12.9-fold enhancement compared to pristine PTA nanosheets exhibiting competitive photoactivity among reported perylene-based materials.Femtosecond transient absorption spectra,in-situ diffuse reflectance infrared Fourier transform spectra and theoretical calculations reveal that the exceptional performance is attributed to the enhanced electron transfer from PTA to rGO via the phosphate bridge and then to the Co-N_(4),and to the promoted O_(2)adsorption and activation at Co-N_(4)active sites.This work provides a feasible and effective strategy for designing highly efficient single-atom semiconductor heterojunction photocatalysts for H_(2)O_(2)production.
基金supported by National Natural Science Foundation of China(Nos.52307239,52102300,52207234)the Natural Science Foundation of Hubei Province(Nos.2022CFB1003,2021CFA025).
文摘Conversion-type anode materials are highly desirable for Na-ion batteries(NIBs)due to their high theoretical capacity.Nevertheless,the active materials undergo severe expansion and pulverization during the sodiation,resulting in inferior cycling stability.Herein,a self-supporting three-dimensional(3D)graphene sponge decorated with Fe_(2)O_(3)nanocubes(rGO@Fe_(2)O_(3))is constructed.Specifically,the 3D graphene sponge with resilience and high porosity benefits to accommodate the volume expansion of the Fe_(2)O_(3)nanocubes and facilitates the rapid electrons/ions transport,enabling spatial confinement to achieve outstanding results.Besides,the free-standing rGO@Fe_(2)O_(3)can be directly used as an electrode without additional binders and conductive additives,which helps to obtain a higher energy density.Based on the total mass of the rGO@Fe_(2)O_(3)material,the rGO@Fe_(2)O_(3)anode presents a specific capacity of 859 mAh/g at 0.1 A/g.It also delivers an impressive cycling performance(327 mAh/g after 2000 cycles at 1 A/g)and a superior rate capacity(162mAh/g at 20 A/g).The coin-type Na_(3)V_(2)(PO_(4))_(3)@C//rGO@Fe_(2)O_(3)NIB exhibits an energy density of 265.3Wh/kg.This unique 3D ionic/electronic conductive network may provide new strategies to design advanced conversion-type anode materials for high-performance NIBs.
基金Funded by the National Natural Science Foundation of China(No.51972242)the National College Students'Innovation and Entrepreneurship Training Program(No.202210488020)+2 种基金the Open Fund of the Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steel making(Wuhan University of Science and Technology)of China(No.KF-20-5)the Research Project of Yingcheng Xinjincheng Environmental Protection Technology Co.,Ltd(No.2023420612000754)the Program(No.BG20210227001)of High-end Foreign Experts of the State of the State Administration of Foreign Experts Affairs(SAFEA)。
文摘In this study,the holey graphene was prepared by microwave-assisted chemical etching.The three-dimensional(3D)holey graphene hydrogel was obtained through hydrothermal self-assembly method,followed by the introduction of FeCo_(2)S_(4)particles.The resulting holey graphene hydrogel,characterized by high specific surface area and abundant pores combined with FeCo_(2)S_(4)with high pseudocapacitance by interfacial interaction,shortened the mass transport path and enhanced the specific capacitance.The findings reveal that the holey graphene hydrogel/FeCo_(2)S_(4)(FeCo_(2)S_(4)/HGH)composite exhibits high specific capacitance and impressive rate capability(413.4 F·g^(-1)at 1 A·g^(-1),300.4 F·g^(-1)at 6 A·g^(-1)).The symmetric supercapacitor operated within a stable potential window of 0.1-1.6 V,achieving specific capacitance of 127.5 F·g^(-1)at 1 A·g^(-1),and can deliver 37.1 Wh·kg^(-1)at a power density of 1499 W·kg^(-1).Besides,under the current density of 3 A·g^(-1),the supercapacitor retained 90.8%of its capacitance after 5000 cycles,demonstrating exceptional cycle stability.This study presents an efficient method for fabricating advanced integrated supercapacitors electrodes with enhanced energy density.
基金supported by the National Natural Science Foundation of China(22278347)the Excellent Doctoral Student Research Innovation Project of Xinjiang University of China(XJU2022BS048)the Postgraduate Innovation Project of Xinjiang Uygur Autonomous Region of China(XJ2023G027).
文摘Low-cost Fe-based disordered rock salt(DRX)Li_(2)FeTiO_(4)is capable of providing high capacity(295 mA h g^(-1))by redox activity of cations(Fe^(2+)/Fe^(4+)and Ti^(3+)/Ti^(4+))and anionic oxygen.However,DRX structures lack transport channels for ions and electrons,resulting in sluggish kinetics,poor electrochemical activity,and cyclability.Herein,graphene conductive carbon network permeated Li_(2)FeTiO_(4)(LFT/C/G)nanofibers are successfully prepared by a facile sol-gel assisted electrospinning method.Ultrafine Li_(2)FeTiO_(4)nanoparticles(2 nm)and one-dimensional(1D)structure provide abu ndant active sites and unobstructed diffu sion channels,accelerating ion diffusion.In addition,introducing graphene reduces the band gap and Li^(+)diffusion barrier and improves the dynamic properties of Li_(2)FeTiO_(4),thus achieving a relatively mild interfacial reaction and reversible redox reaction.As expected,the LFT/C/1.0G cathode delivers a remarkable discharge capacity(238.5 mA h g^(-1)),high energy density(508.8 Wh kg^(-1)),and excellent rate capability(51.2 mA hg^(-1)at 1.0 A g^(-1)).Besides,the LFT/C/1.0G anode also displays a high capacity(514.5 mA h g^(-1)at 500 mA g^(-1))and a remarkable rate capability(243.9 mA h g^(-1)at 8 A g^(-1)).Moreover,the full batteries based on the LFT/C/1.0G symmetric electrode demonstrate a reversible capacity of 117.0 mA h g^(-1)after 100 cycles at 50 mA g^(-1).This study presents useful insights into developing cost-effective DRX cathodes with durable and fast lithium storage.
文摘ZrO2/Graphene nanocomposites are fabricated from graphene oxide by one-step, green, facile and low-cost SCCO2 method. The as-prepared nanocomposites are characterized by means of X-ray photoelectron, transmission electron microscopy and catalytic chemiluminescence measurement. The ZrO2 nanoparticles with size of several nanometers are uniformly coated on the graphene surface. The chemiluminescence characteristic to ethanol of the as-prepared nanocomposite paper is also investigated. The nanocomposite paper obtained displays high catalytic chemiluminescence sensitivity and highly selectivity to the ethanol gas. This study provides a facile, green and low-cost route to prepare nanoscopic gas sensing devices with application in safe protection, food fermentation, medical process and traffic safe.
基金financially supported by the Natural Science Foundation of Jiangsu Province(No.BK20211352)the Nature Science Fundation of Jiangsu Higher Education Institutions of China(No.22KJA430005)。
文摘The synthesis of a perpendicular growth structure of MoS_(2)nanosheets on graphene for efficient sodium storage is challenging yet ideal due to the benefits of open ion diffusion channels and high electronic conductivity.In this study,we have successfully fabricated a novel structure of vertical MoS_(2)nanosheets on graphene,with ZnS nanoparticles serving as bonding points(MoS_(2)/ZnS/G),through a facile hydrothermal method.During the synthesis process,Zn^(2+)not only acts as a landing site for the vertical growth of MoS_(2)nanosheets but also triggers the formation of a defect-rich structure in the final samples.This unique architecture of MoS_(2)/ZnS/G effectively combines the advantages of a vertically aligned geometry and a defectrich structure for energy storage.The resulting structure displays shortened transport paths for electrons/ions,enhanced conductivity,improved structural integrity,and an increased number of active sites for promising electrochemical performance.As expected,when used as anode for sodium-ion batteries,the as-synthesize d MoS_(2)/ZnS/G exhibits excellent rate capability(high capacity of 298 mAh·g^(-1)at 5 A·g^(-1))and good cycling stability(a capacity decay of 0.056%per cycle after 500 cycles at 1 A·g^(-1)).According to the kinetic investigations,the electrochemical process of the MoS_(2)/ZnS/G sample is primarily governe d by a pseudocapacitive behavior,which enhances the charge/discharge kinetics and allows the MoS_(2)/ZnS/G structure to remain intact during cycling.
基金Project(2108085ME184)supported by the Natural Science Foundation of Anhui Province,ChinaProject(2022AH010019)supported by the Innovation Team Project of Anhui Provincial Department of Education,China+1 种基金Project(GXXT-2021-057)supported by the Collaborative Innovation Project of Anhui Provincial Department of Education,ChinaProject(2020QDZ36)supported by the Doctoral Scientific Research Startup Foundation of Anhui Jianzhu University,China。
文摘Manganese ferrite(MnFe_(2)O_(4))has the advantages of simple preparation,high resistivity,and high crystal symmetry.Herein,we have developed an electrochemical sensor utilizing graphene and MnFe_(2)O_(4) nanocomposites modified glassy carbon electrode(GCE),which is very efficient and sensitive to detect bisphenol A(BPA).MnFe_(2)O_(4)/graphene(GR)was synthesized by immobilizing the MnFe_(2)O_(4) microspheres on the graphene nanosheets via a simple one-pot solvothermal method.The morphology and structure of the MnFe_(2)O_(4)/GR nanocomposite have been characterized through scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).In addition,electrochemical properties of the modified materials are comparably explored by means of cyclic voltammetry(CV),electrochemical impedance spectroscopy(EIS)and differential pulse voltammetry(DPV).Under the optimal conditions,the proposed electrochemical sensor for the detection of BPA has a linear range of 0.8-400μmol/L and a detection limit of 0.0235μmol/L(S/N=3)with high sensitivity,good selectivity and high stability.In addition,the proposed sensor was used to measure the content of BPA in real water samples with a recovery rate of 97.94%-104.56%.At present,the synthesis of MnFe_(2)O_(4)/GR provides more opportunities for the electrochemical detection of BPA in practical applications.
基金financially supported by the NSF of China(No.61871180)2022 Special Project for the Construction of Innovative Provinces to Fight the COVID-19 Outbreak(No.2022SK2115)+1 种基金Natural Science Foundation of Hunan Province of China(Nos.2022JJ30230,2021JJ30213)the Deanship of Scientific Research,Taif University。
文摘A novel approach was developed to fabricate a label-free electrochemical aptasensor for specific detection of mercury ions(Hg^(2+)).This involved modifying polylysine(PLL)-coated black phosphorus-porous graphene(BP-PG)nanocomposites(PLL/BP-PG)onto the surface of glassy carbon electrodes(GCE),which were further modified with gold nanoparticles(AuNPs)to combine with a thiolated aptamer(Apt)capable of specifically recognizing Hg^(2+).BP-PG was synthesized using the solvothermal method and covalently bonded to form BP-PG nanosheets,resulting in significant enhanced electrochemical properties of the PLL/BP-PG composite.Furthermore,the PLL/BP-PG composite was improved environmental stability of BP and provided a considerable quantity of-NH_(2)for bonding to Au NPs firmly by assembling.The physical properties and electrochemical behavior of the substrate materials were investigated using various characterization techniques,and analytical parameters were optimized.It is shown that,the Apt/AuNPs/PLL/BP-PG/GCE had a linear response(R~2=0.999)with good selectivity and high sensitivity over the Hg^(2+)range of 1-10,000 nmol/L.The proposed sensor has a detection limit of 0.045 nmol/L and can be employed for detecting of Hg^(2+).It also obtained satisfying results in river water,soil and vegetable samples.
基金financially supported by the National Natural Science Foundation of China (Nos.U2002212,52102058,52204414,52204413,and 52204412)the National Key R&D Program of China (Nos.2021YFC1910504,2019YFC1907101,2019YFC1907103,and 2017YFB0702304)+7 种基金the Key R&D Program of Ningxia Hui Autonomous Region,China (Nos.2021BEG01003 and2020BCE01001)the Xijiang Innovation and Entrepreneurship Team,China (No.2017A0109004)the Macao Young Scholars Program (No.AM2022024),Chinathe Beijing Natural Science Foundation (Nos.L212020 and 2214073),Chinathe Guangdong Basic and Applied Basic Research Foundation,China (Nos.2021A1515110998 and 2020A1515110408)the China Postdoctoral Science Foundation (No.2022M710349)the Fundamental Research Funds for the Central Universities,China (Nos.FRF-BD-20-24A,FRF-TP-20-031A1,FRF-IC-19-017Z,and 06500141)the Integration of Green Key Process Systems MIIT and Scientific and Technological Innovation Foundation of Foshan,China(Nos.BK22BE001 and BK21BE002)。
文摘Exclusive responsiveness to ultraviolet light (~3.2 eV) and high photogenerated charge recombination rate are the two primary drawbacks of pure TiO_(2). We combined N-doped graphene quantum dots (N-GQDs), morphology regulation, and heterojunction construction strategies to synthesize N-GQD/N-doped TiO_(2)/P-doped porous hollow g-C_(3)N_(4) nanotube (PCN) composite photocatalysts (denoted as G-TPCN). The optimal sample (G-TPCN doped with 0.1wt% N-GQD, denoted as 0.1% G-TPCN) exhibits significantly enhanced photoabsorption, which is attributed to the change in bandgap caused by elemental doping (P and N), the improved light-harvesting resulting from the tube structure, and the upconversion effect of N-GQDs. In addition, the internal charge separation and transfer capability of0.1% G-TPCN are dramatically boosted, and its carrier concentration is 3.7, 2.3, and 1.9 times that of N-TiO_(2), PCN, and N-TiO_(2)/PCN(TPCN-1), respectively. This phenomenon is attributed to the formation of Z-scheme heterojunction between N-TiO_(2) and PCNs, the excellent electron conduction ability of N-GQDs, and the short transfer distance caused by the porous nanotube structure. Compared with those of N-TiO_(2), PCNs, and TPCN-1, the H2 production activity of 0.1%G-TPCN under visible light is enhanced by 12.4, 2.3, and 1.4times, respectively, and its ciprofloxacin (CIP) degradation rate is increased by 7.9, 5.7, and 2.9 times, respectively. The optimized performance benefits from excellent photoresponsiveness and improved carrier separation and migration efficiencies. Finally, the photocatalytic mechanism of 0.1% G-TPCN and five possible degradation pathways of CIP are proposed. This study clarifies the mechanism of multiple modification strategies to synergistically improve the photocatalytic performance of 0.1% G-TPCN and provides a potential strategy for rationally designing novel photocatalysts for environmental remediation and solar energy conversion.
基金financial support from the National Natural Science Foundation of China(22202217)the National Natural Science Foundation of Gansu(24JRRA046)+1 种基金the Department of Science&Technology of Shandong Province for their assistance(2023CXGC010607)the Joint Fund of Shandong Energy Institute and Enterprise(SEI U202308)。
文摘Developing innovative catalysts continues to be a pivotal interest within the heterogeneous catalysis area.The carbonaceous material ND@G,featuring a sp^(2)/sp^(3)hybrid architecture,comprises a nanodiamond(ND)core structure encased within an ultrathin graphitic nanoshell(G),and has been widely exploited as a metal-free catalyst or a support for metal catalyst.Its unique curved zero-dimensional structure/surface and tunable defective surface characteristics endow it with outstanding performance in different heterogeneous catalytic systems.The present review summarized the construction of the diverse types of ND@G and a wide-ranging valorization of structure-activity relation with its catalytic mechanism in various reactions.The recent advancements in the impact of active sites’architecture and the interaction between metal and support(preventing the as-formed metal species migration and agglomeration based on ND@G)on the catalytic performance of supported metal catalysts are particularly highlighted.The current challenges and outlooks/opportunities confronted by ND@G materials in catalysis are prospected by virtue of its fundamental physicochemical characterizations and potential catalytic estimation.This in-depth analysis seeks to pave the way for effective utilizing the ND@G in catalytic processes.Based on our knowledge,we also identify the challenges along with this area and offer some perspectives on how to overcome them.
基金Funded by the Open/Innovation Fund of Hubei Three Gorges Laboratory(No.SK212002)。
文摘A hierarchical reduced graphene oxide-MnO_(2)@polypyrrole coaxial nanotube composite hydrogel was prepared via oxidative polymerization of pyrrole in the presence of MnO_(2)nanotubes,followed by the hydrothermal treatment of graphene oxide and MnO_(2)@polypyrrole coaxial nanotubes.The stable composite hydrogel with a hierarchical network was composed of one-dimensional MnO_(2)@polypyrrole coaxial nanotube and two-dimensional graphene nanosheet and characterized by scanning electron microscope,Fourier transform infrared spectroscopy,X-ray diffraction,Brunauer-Emmett-Teller surface,and X-ray photoelectron spectroscopy measurements.The composite hydrogel can be used as an efficient adsorbent for Cr(Ⅵ)removal due to the synergistic interaction between graphene and MnO_(2)@polypyrrole and the hierarchical structure of the hydrogel.Moreover,the composite hydrogel is easily separated because of its stable monolith,and it is reusable(76.8%of removal ability remaining after five adsorption-desorption cycles).The simple fabrication and cost-effective separation process together with the excellent absorption performance endow the composite hydrogel with great potential for practical wastewater treatment.
基金financially supported by The Natural Science Foundation of the Jiangsu Higher Education Institutions of China(22KJB530007,22KJA530001)National Natural Science Foundation of China(22208151)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20220002)the State Key Laboratory of MaterialsOriented Chemical Engineering(SKL-MCE-22B07).
文摘For the application of carbon capture by membrane process,it is crucial to develop a highly permeable CO_(2)-selective membrane.In this work,we reported an ultra-thin polyether-block-amide(Pebax)mixedmatrix membranes(MMMs)incorporated by graphene oxide(GO),in which the interlayer channels were regulated to optimize the CO_(2)/N_(2) separation performance.Various membrane preparation conditions were systematically investigated on the influence of the membrane structure and separation performance,including the lateral size of GO nanosheets,GO loading,thermal reduction temperature,and time.The results demonstrated that the precisely regulated interlayer channel of GO nanosheets can rapidly provide CO_(2)-selective transport channels due to the synergetic effects of size sieving and preferential adsorption.The GO/Pebax ultra-thin MMMs exhibited CO_(2)/N_(2) selectivity of 72 and CO_(2) permeance of 400 GPU(1 GPU=106 cm^(3)(STP)·cm^(2)·s^(-1)·cmHg^(-1)),providing a promising candidate for CO_(2) capture.
