Gallium nitride(GaN)single crystal with prominent electron mobility and heat resistance have great potential in the high temperature integrate electric power systems.However,the sluggish charge storage kinetics and in...Gallium nitride(GaN)single crystal with prominent electron mobility and heat resistance have great potential in the high temperature integrate electric power systems.However,the sluggish charge storage kinetics and inadequate energy densities are bottlenecks to its practical application.Herein,the self-supported GaN/Mn_(3)O_(4) integrated electrode is developed for both energy harvesting and storage under the high temperature environment.The experimental and theoretical calculations results reveal that such integrated structures with Mn-N heterointerface bring abundant active sites and reconstruct low-energy barrier channels for efficient charge transferring,reasonably optimizing the ions adsorption ability and strengthening the structural stability.Consequently,the assembled GaN based supercapacitors deliver the power density of 34.0 mW cm^(-2) with capacitance retention of 81.3%after 10000 cycles at 130℃.This work innovatively correlates the centimeter scale GaN single crystal with ideal theoretical capacity Mn_(3)O_(4) and provides an effective avenue for the follow-up energy storage applications of the wide bandgap semiconductor.展开更多
In recent years,numer-ous single-atom catalysts(SACs)have been synthesized to activate persulfate(PS)by a non-radical pathway because of its high se-lectivity,and activity for the cata-lyst.Metal-nitrogen-carbon(M-N_(...In recent years,numer-ous single-atom catalysts(SACs)have been synthesized to activate persulfate(PS)by a non-radical pathway because of its high se-lectivity,and activity for the cata-lyst.Metal-nitrogen-carbon(M-N_(x)-C)has been identified as the key active site in SACs.Although methods for preparing SACs have been extensively reported,a systematic summary of the direct construction of M-N_(x)-C,espe-cially unconventional metal-nitrogen-carbon(UM-N_(x)-C,x≠4),on SACs for PS non-radical activation has still not been reported.The role of the M-N_(x)-C active sites on PS non-radical activation is discussed and methods for the formation of M-N_(x)-C and UM-N_(x)-C active sites in SACs and the effect of catalyst carriers such as carbon nitride(g-C_(3)N_(4)),MOFs,COFs,and other car-bon materials are reviewed.Direct and indirect methods,especially for UM-N_(x)-C active site formation,are also elaborated.Factors affecting the formation of a M-N_(x)-C active site on SACs are also discussed.Prospects for the use of M-N_(x)-C active sites for the non-radical activation of PS by SACs to remove organic contaminants from wastewater are evaluated.展开更多
Cu/ZnO-based catalysts are widely employed for methanol synthesis via CO_(2) hydrogenation.The preparation procedure is sensitive to the particle size and interfacial structure,which are considered as potential active...Cu/ZnO-based catalysts are widely employed for methanol synthesis via CO_(2) hydrogenation.The preparation procedure is sensitive to the particle size and interfacial structure,which are considered as potential active centers influencing the rate of both methanol and CO formation.The particle size and the interaction between Cu and the support materials are influenced by the coprecipitation conditions,let alone that the mechanistic divergence remains unclear.In this work,a series of Cu/ZnO/ZrO_(2) catalysts were prepared via co-precipitation at different pH value and systematically characterized.The structure has been correlated with kinetic results to establish the structure-performance relationship.Kinetic analysis demonstrates that methanol synthesis follows a single-site Langmuir-Hinshelwood(L-H)mechanism,i.e.,Cu serves as the active site where CO_(2) and H_(2) competitively adsorb and react to form methanol.In contrast,CO formation proceeds via a dual-site L-H mechanism,where CO_(2) adsorbs onto ZnO and H_(2) onto Cu,with the reaction occurring at the Cu/ZnO interface.Therefore,for the direct formation of methanol,solely reducing the particle size of Cu would not be beneficial.展开更多
The quest for sustainable energy solutions has intensified the search for alternative feedstocks that can supplement or replace fossil fuels. Obtaining fuels or chemicals through the conversion of renewable biomass is...The quest for sustainable energy solutions has intensified the search for alternative feedstocks that can supplement or replace fossil fuels. Obtaining fuels or chemicals through the conversion of renewable biomass is a promising candidate [1,2]. Some noblemetal-based (e.g., Pt, Pd and Rh) catalysts exhibit significant catalytic activity to the conversion reaction of these biomass.展开更多
Single atom catalysts supported by two-dimensional(2D)materials,including graphene,g-C_(3)N_(4),and graphdiyne,ex-hibit promising electrocatalytic nitrogen reduction reaction(NRR)activity.Nevertheless,sometimes theore...Single atom catalysts supported by two-dimensional(2D)materials,including graphene,g-C_(3)N_(4),and graphdiyne,ex-hibit promising electrocatalytic nitrogen reduction reaction(NRR)activity.Nevertheless,sometimes theoretical works failed to predict the high activity of NRR of single atom cat-alysts,especially for Fe,Co,Mn,Cu,Ru.In this work,based on DFT calculations,it is suggested that dual-atom sites on N doped graphene(M_(2)@N-graphene)rather than single-atom sites are more likely to be the active sites for NRR.Notably,Fe_(2)@N_(3),Co_(2)@N_(2),Mn_(2)@N_(2),Cu_(2)@N_(1),and Ru_(2)@N_(3)endow the best catalytic activity with corresponding limiting potentials of-0.26,-0.18,-0.17,-0.39,and-0.30 V,re-spectively.Furthermore,on g-C_(3)N_(4)and graphdiyne,triple-atom sites(TAS,M_(3))such as Ru_(3)(Co_(3))@g-C_(3)N_(4)and Ru_(3)(Rh_(3))@graphdiyne are expected to exhibit higher stability and NRR catalytic performance than single-atom sites(SAS)and dual-atom sites(DAS),with corresponding limiting potentials of-0.28,-0.48,-0.24,and-0.23 V.The calculated results with the corresponding experimental potentials indicate that the origin of superior NRR ac-tivity observed in experiments may be contributed by M_(2)or M_(3)on 2D materials.This study provides an in-depth investigation into real active NRR sites of metal atoms supported on 2D materials and contributes to the design of effective NRR catalysts.展开更多
A comprehensive understanding of the structure and dynamic evolution of catalytic active sites is vital for advancing the study of liquid-phase acetylene hydrochlorination.Here,we successfully developed a Ru-DIPEA/TMS...A comprehensive understanding of the structure and dynamic evolution of catalytic active sites is vital for advancing the study of liquid-phase acetylene hydrochlorination.Here,we successfully developed a Ru-DIPEA/TMS catalyst optimised through systematic composition and condition tuning,demonstrating exceptional performance with 95.5%C_(2)H_(2)conversion and sustaining over 91.1%activity along with nearly 100%selectivity for VCM during a continuous 900-h test.Using a combination of characterisation techniques,including UV–vis spectroscopy,FT-IR spectroscopy,X-ray photoelectron spectroscopy,singlecrystal X-ray diffraction,and X-ray absorption spectroscopy,along with density functional theory(DFT)calculations,the structure and dynamic behaviour of the active sites were thoroughly investigated under the synergistic influence of ligands and HCl.The results revealed that HCl activation induces a significant structural transformation of the active sites,leading to the formation of a hexacoordinate complex,Ru(CO)_(2)C_(12)(C_(6)H_(15)N·HCl)_(2).DFT calculations further elucidated the mechanism underlying active site formation,revealing that an increased electron density around the Ru centre and corresponding changes in its coordination environment play critical roles in enhancing catalyst stability and activity.This study contributes to a deeper understanding of the structural basis of active site evolution during acetylene hydrochlorination,offering both practical insights into industrial applications and foundational knowledge for advancing liquid-phase catalysis.展开更多
Urchin-like W_(18)O_(49),with a large specific surface area(113.738 m^(2)g^(-1))and abundant oxygen vacancies(OVs),was prepared using an active sites tuning and microstructure engineering method.This material was appl...Urchin-like W_(18)O_(49),with a large specific surface area(113.738 m^(2)g^(-1))and abundant oxygen vacancies(OVs),was prepared using an active sites tuning and microstructure engineering method.This material was applied for U(Ⅵ)adsorption for the first time,demonstrating a high adsorption capacity of 567.55 mg g^(-1),which exceeds that of most inorganic adsorbents.Characterization via active site masking experiments and theoretical calculations,etc.,indicated that the excellent adsorption performance toward U(Ⅵ)was due to strong complexation between UO_(2)^(2+)and W–O bond of W_(18)O_(49),facile oxygen vacancy adsorption,and interface electron transfer from W^(5+)to UO_(2)^(2+),which acted as a reducing agent,partially converting U(Ⅵ)to U(IV).Furthermore,W_(18)O_(49)exhibited practical applicability with a removal rate exceeding 82%after 5 cycles,a 92.79%removal rate for real uranium-containing wastewater,and a high uranium recovery rate of 75.96%.Additionally,the synergistic adsorption-photocatalytic effect significantly enhanced U(Ⅵ)extraction,reaching an extraction capacity of 988.0mg g^(-1).This work provides a promising strategy for developing highly efficient U(Ⅵ)WO_(3)-based adsorbents.展开更多
Efficient recognition and selective capture of NH_(3)is not only beneficial for increasing the productivity of the synthetic NH_(3)industry but also for reducing air pollution.For this purpose,a group of deep eutectic...Efficient recognition and selective capture of NH_(3)is not only beneficial for increasing the productivity of the synthetic NH_(3)industry but also for reducing air pollution.For this purpose,a group of deep eutectic solvents(DESs)consisting of glycolic acid(GA)and phenol(PhOH)with low viscosities and multiple active sites was rationally designed in this work.Experimental results show that the GA^(+)PhOH DESs display extremely fast NH_(3)absorption rates(within 51 s for equilibrium)and high NH_(3)solubility.At 313.2 K,the NH_(3)absorption capacities of GA^(+)PhOH(1:1)reach 6.75 mol/kg(at 10.7 kPa)and 14.72 mol/kg(at 201.0 kPa).The NH_(3)solubility of GA^(+)PhOH DESs at low pressures were minimally changed after more than 100 days of air exposure.In addition,the NH_(3)solubility of GA^(+)PhOH DESs remain highly stable in 10 consecutive absorption-desorption cycles.More importantly,NH_(3)can be selectively captured by GA^(+)PhOH DESs from NH_(3)/CO_(2)/N_(2)and NH_(3)/N_(2)/H_(2)mixtures.1H-NMR,Fourier transform infrared and theoretical calculations were performed to reveal the intrinsic mechanism for the efficient recognition of NH_(3)by GA^(+)PhOH DESs.展开更多
Electrocatalytic conversion of carbon dioxide(CO_(2))offers an effective method of CO_(2)fixation to mitigate global warming and the energy crisis.However,for supported Ni single-atom catalysts(SACs),which are among t...Electrocatalytic conversion of carbon dioxide(CO_(2))offers an effective method of CO_(2)fixation to mitigate global warming and the energy crisis.However,for supported Ni single-atom catalysts(SACs),which are among the most promising candidates for this application,the relationship between Ni coordination structure and catalytic properties is still under strong debate.Here,we fabricated a series of Ni SACs through precise-engineering of anchor sites on nitrogen-doped carbon(NC)followed by Ni atom anchoring using atomic layer deposition.Among them,a Ni_(1)/NC SAC,with a coordination number(CN)of four but less pyridinic nitrogen(N_(pyri)),achieved over 90%faradaic efϐiciency for CO at potentials from-0.7 to-1.0 V and a mass activity of 6.5 A/mgNi at-0.78 V along with high stability,outperforming other Ni SACs with lower CN and more N_(pyri).Theoretical calculations of various three and four-coordinated Ni_(1)-NxCy structures revealed a linear correlation between the reaction Gibbs free energy for the potential-limiting step and the highest occupied molecular orbital(HOMO)position of Ni-3d orbitals,therein the four-coordinated Ni_(1)-N_(1)C_(3)with the highest HOMO position is identified as the active site for the electrocatalytic CO_(2)-to-CO process,in line with the experimental results.展开更多
The electrochemical reduction of carbon dioxide(CO_(2)RR)is a promising strategy for achieving carbon neutralization.The Ni-N_(4) site is well known as the active site in metal single atoms on N-doped carbon catalysts...The electrochemical reduction of carbon dioxide(CO_(2)RR)is a promising strategy for achieving carbon neutralization.The Ni-N_(4) site is well known as the active site in metal single atoms on N-doped carbon catalysts,while its symmetric charge distribution nature is not favorable for electron transfer and then hindering the efficient CO_(2)RR.Herein,we constructed a Ni SA/CNs single-atom catalyst.Notably,it features unique Ni-N_(4)-O active sites,featuring one axial O atom and four planar N atoms,constituting a broken symmetrical electronic structure of Ni-N_(4) sites.Furthermore,hierarchical pore structures were obtained with the assistance of NaNO_(3) pore-forming agent during thermal treatment process,which promote electronic and mass transfer.And the resulting high specific surface area can host more Ni-N_(4)-O active sites.These specialized active sites promote the key intermediate(∗CO)adsorption/desorption and suppresses hydrogen evolution.Consequently,the Ni SA/CNs catalyst exhibits a high turnover frequency(TOF)value,reaching 34,081 h^(-1) at-0.98 V vs.RHE.Additionally,it achieves an excellent CO Faradaic efficiency,exceeding 90%,over a wide potential range from-0.4 V to-1.0 V vs.RHE.This work not only offers a new method for the rational synthesize single-atom catalysts with unique Ni-N_(4)-O active sites,but also provides in-depth insight into the origin of catalytic activity of porous carbon-base catalysts.展开更多
Single-atom catalysts are promising for H_(2)O_(2) photosynthesis from O_(2) and H_(2)O,but their efficiency is still limited by the ill-defined electronic structure.In this study,Co single-atoms with unique four plan...Single-atom catalysts are promising for H_(2)O_(2) photosynthesis from O_(2) and H_(2)O,but their efficiency is still limited by the ill-defined electronic structure.In this study,Co single-atoms with unique four planar N-coordination and one axial P-coordination(Co-N_(4)P_(1))are decorated on the lateral edges of nanorod-like crystalline g-C_(3)N_(4)(CCN)photocatalysts.Significantly,the electronic structures of central Co as active sites for O_(2) reduction reaction(ORR)and planar N-coordinator as active sites for H_(2)O oxidation reaction(WOR)in Co-N_(4)P_(1) can be well regulated by the synergetic effects of introducing axial P-coordinator,in contrast to the decorated Co single-atoms with only four planar N-coordination(Co-N_(4)).Specifically,directional photoelectron accumulation at central Co active sites,induced by an introduced midgap level in Co-N_(4)P_(1),mediates the ORR active sites from 4e–-ORR-selective terminal–NH_(2) sites to 2e–-ORR-selective Co sites,moreover,an elevated d-band center of Co 3d orbital strengthens ORR intermediate*OOH adsorption,thus jointly facilitating a highly selective and active 2e^(–)-ORR pathway to H_(2)O_(2) photosynthesis.Simultaneously,a downshifted p-band center of N_(2)p orbital in Co-N_(4)P_(1) weakens WOR intermediate*OH adsorption,thus enabling a preferable 2e^(–)-WOR pathway toward H_(2)O_(2) photosynthesis.Subsequently,Co-N_(4)P_(1) exhibits exceptional H_(2)O_(2) photosynthesis efficiency,reaching 295.6μmol g^(-1) h^(-1) with a remarkable solar-to-chemical conversion efficiency of 0.32%,which is 15 times that of Co-N_(4)(19.2μmol g^(-1) h^(-1))and 10 times higher than CCN(27.6μmol g^(-1) h^(-1)).This electronic structure modulation on single-atom catalysts offers a promising strategy for boosting the activity and selectivity of H_(2)O_(2) photosynthesis.展开更多
The insufficient active sites and slow interfacial charge trans-fer of photocatalysts restrict the efficiency of CO_(2) photoreduction.The synchronized modulation of the above key issues is demanding and chal-lenging....The insufficient active sites and slow interfacial charge trans-fer of photocatalysts restrict the efficiency of CO_(2) photoreduction.The synchronized modulation of the above key issues is demanding and chal-lenging.Herein,strain-induced strategy is developed to construct the Bi–O-bonded interface in Cu porphyrin-based monoatomic layer(PML-Cu)and Bi_(12)O_(17)Br_(2)(BOB),which triggers the surface interface dual polarization of PML-Cu/BOB(PBOB).In this multi-step polarization,the built-in electric field formed between the interfaces induces the electron transfer from con-duction band(CB)of BOB to CB of PML-Cu and suppresses its reverse migration.Moreover,the surface polarization of PML-Cu further promotes the electron converge in Cu atoms.The introduction of PML-Cu endows a high density of dispersed Cu active sites on the surface of PBOB,significantly promoting the adsorption and activation of CO_(2) and CO desorption.The conversion rate of CO_(2) photoreduction to CO for PBOB can reach 584.3μmol g-1,which is 7.83 times higher than BOB and 20.01 times than PML-Cu.This work offers valuable insights into multi-step polarization regulation and active site design for catalysts.展开更多
The efficient separation and collection of ammonia(NH_(3))during NH_(3) synthesis process is essential to improve the economic efficiency and protect the environment.In this work,ethanolammonium hydrochloride(EtOHACl)...The efficient separation and collection of ammonia(NH_(3))during NH_(3) synthesis process is essential to improve the economic efficiency and protect the environment.In this work,ethanolammonium hydrochloride(EtOHACl)and phenol(PhOH)were used to prepare a novel class of deep eutectic solvents(DESs)with multiple active sites and low viscosities.The NH_(3) separation performance of EtOHACl+PhOH DESs was analyzed completely.It is figured out that the NH_(3) absorption rates in EtOHACl+PhOH DESs are very fast.The NH_(3) absorption capacities are very high and reach up to 5.52 and 10.74 mol·kg1 at 11.2 and 100.4 kPa under 298.2 K,respectively.In addition,the EtOHACl+PhOH DESs present highly selective absorption of NH_(3) over N_(2) and H_(2) and good regenerative properties after seven cycles of absorption/desorption.The intrinsic separation mechanism of NH_(3) by EtOHACl+PhOH DESs was further revealed by spectroscopic analysis and quantum chemistry calculations.展开更多
Though Zn-air batteries(ZABs)are one of the most promising system for energy storage and conversion,challenge still persists in its commercial application due to the sluggish kinetics of oxygen reduction/evolution rea...Though Zn-air batteries(ZABs)are one of the most promising system for energy storage and conversion,challenge still persists in its commercial application due to the sluggish kinetics of oxygen reduction/evolution reaction(ORR/OER).Hereby,a polyvinylidene fluoride(PVDF)-assisted pyrolysis strategy is proposed to develop a novel corrugated plate-like bifunctional electrocatalyst using two-dimensional zeolitic imidazolate frameworks(2D ZIF-67)as the precursor.The employed PVDF plays an important role in inheriting the original 2D structure of ZIF-67 and modulating the composition of the final products.As a result,a corrugated plate-like electrocatalyst,high-density Co nanoparticles decorated 2D Co,N,and F tri-doped carbon nanosheets,can be obtained.The acquired electrocatalyst enables efficient active sites and rapid mass transfer simultaneously,thus showing appreciable electrocatalytic performance for rechargeable Zn-air batteries.Undoubtedly,our proposed strategy offers a new perspective to the design of advanced oxygen electrocatalysts.展开更多
Given the clean and inexhaustible solar energy from solar light,photocatalytic ammonia synthesis is extremely appealing.However,high electron-hole recombination rates and insufficient active sites severely limited N2 ...Given the clean and inexhaustible solar energy from solar light,photocatalytic ammonia synthesis is extremely appealing.However,high electron-hole recombination rates and insufficient active sites severely limited N2 photoreaction reduction.Herein,we designed and fabricated FeCu alloy nanoparticles anchored on carbon nitride nanosheets with excellent photocatalyt ic ammonia synthesis performance.As a coupler between Fe and carbon nitride,Cu promotes the separation of photogenerated charge carriers in carbon nitride under solar light irradiation,and renters the semiconductor a forceful electron donor for the Fe active sites.The accumulated electrons at Fe sites furtherly facilitated the adsorption and activation of the molecular nitrogen.Besides,the uniform dispersed FeCu alloy nanoparticles were on carbon nitride nanosheets enhanced the stability of photocataly tic nitrogen reduction reaction,making the artificial photocataly tic ammonia synthesis more sustainable for application.This work highlights that a direct electron transfer channel can be used to regulate the photochemical nitrogen fixation network.展开更多
In electrochemical energy devices,the operating conditions always exert enormous influence on electrocatalysts'performances.Phosphoric acid(PA),acted as the proton carriers,can be adsorbed on Pt surface,block acti...In electrochemical energy devices,the operating conditions always exert enormous influence on electrocatalysts'performances.Phosphoric acid(PA),acted as the proton carriers,can be adsorbed on Pt surface,block active sites and affect the electronic structure of Pt unfavorably,which severely restricts the performance of high-temperature proton exchange membrane fuel cells(HT-PEMFCs).Herein,simply basic organic compounds,such as dicyandiamide(DCD),melamine(Mel)and cyanuric acid(CA),are decorated on Pt surface(DCD-Pt/C,Mel-Pt/C and CA-Pt/C)to induce the adsorption transfer of proton carriers.The decoration can not only inject electrons to Pt and enhance oxygen reduction reaction(ORR)activity but also can induce PA to transfer from Pt surface to organic compounds,decontaminating active sites.In addition,the organic compounds with the larger conjugated system and the smaller electronegativity of ligating atoms would have a greater interaction with Pt,causing a larger decoration amount on Pt surface,which leads to more excellent ORR activity and resistance to PA blockage effect.Therefore,MelPt/C shows a peak power density of 629 mW/cm^(2),exceeding commercial Pt/C(437 mW/cm^(2)),DCD-Pt/C(539 m W/cm^(2))and CA-Pt/C(511 mW/cm^(2))with the same loading.展开更多
Constructing synergistic active sites and optimizing the cooperative adsorption energies for hydrogen and hydroxyl based intermediates are two essential strategies to improve the sluggish kinetics of hydrogen evolutio...Constructing synergistic active sites and optimizing the cooperative adsorption energies for hydrogen and hydroxyl based intermediates are two essential strategies to improve the sluggish kinetics of hydrogen evolution reaction(HER)in alkaline medium.However,it is still in its infancy to simultaneously achieve these goals,especially for designing a well-defined carrier with multiple hydroxyl adsorption sites.Herein,the Ni(HCO_(3))_(2)nanoplates(NHC)with horizontal interfaces sites of Ni-terminated NiO,NiOOH,NiCOO,and Ni(OH)_(2)were employed as the hydroxyl adsorption active sites,which could anchor Pt particles with hydrogen adsorption active sites,constructing the synergistic active sites(NHC-Pt)for HER catalysis.Evidenced by X-ray photoelectron spectroscopy(XPS)and extended X-ray absorption fine structure(EXAFS),the NHC could affect the chemical state and electronic structure of Pt particles by forming bond of Pt-O which could reduce the reaction energy barriers,facilitate the adsorption of hydrogen and establishment of H–H bond.Furthermore,density functional theory(DFT)theoretical calculation revealed that the related process of hydroxide was the rate-determining step.It is demonstrated the hydroxyl group presents the lowest energy barrier for desorption in the process of HER when the gradual desorption process could be described as a migration from Ni(HCO_(3))_(2)·OH directly or via other Ni-based systems formed after partial decomposition of nickel hydrocarbonate to Ni(OH)_(2)…OH with following desorption.As a result,the NHC-Pt hierarchical nanostructure demonstrated superior activity towards HER in a pH-universal solution.This enhancement can be attributed to the optimized electronic structure of Pt,the migration of hydroxyl group on NHC substrates,and the synergistic effects between the NHC carrier and Pt particles.展开更多
The development of earth-abundant electrocatalysts with high performance for electrochemical CO_(2)reduction(ECR)is of great significance.Cu-based catalysts have been widely investigated for ECR due to their unique ab...The development of earth-abundant electrocatalysts with high performance for electrochemical CO_(2)reduction(ECR)is of great significance.Cu-based catalysts have been widely investigated for ECR due to their unique ability to generate various carbonaceous products,but directing selectivity toward one certain product and identifying the real active sites during ECR are still full of challenge.Here,after the incorporation of CdO into CuO,the Cu_(0.5)Cd_(0.5)-O catalyst achieves a 10.3-fold enhancement for CO selectivity in comparison with CuO,and a CO faradic efficiency nearly 90%with a current density around20 mA cm^(-2)could maintain at least 60 h.Interestingly,a wide CO/H_(2)ratio(0.07-10)is reached on Cu_(x)Cd_(1-x)-O catalysts by varying the Cu/Cd ratio,demonstrating the potential of syngas production using such catalysts.The results of ex situ XRD,XPS,and in situ Raman reveal that the real active sites of Cu_(0.5)Cd_(0.5)-O catalysts for CO production during ECR reaction are the reconstructed mixed phases of CuCd alloy and CdCO_(3).In situ FTIR and theoretical calculations further implicate the presence of Cd related species promotes the CO desorption and inhibits the H_(2)evolution,thus leading to an enhanced CO generation.展开更多
Electrocatalytic water splitting has been identified as a potential candidate for producing clean hydrogen energy with zero carbon emission.However,the sluggish kinetics of oxygen evolution reaction on the anode side ...Electrocatalytic water splitting has been identified as a potential candidate for producing clean hydrogen energy with zero carbon emission.However,the sluggish kinetics of oxygen evolution reaction on the anode side of the watersplitting device significantly hinders its practical applications.Generally,the efficiency of oxygen evolution processes depends greatly on the availability of cost‐effective catalysts with high activity and selectivity.In recent years,extensive theoretical and experimental studies have demonstrated that cobalt(Co)‐based nanomaterials,especially low‐dimensional Co‐based nanomaterials with a huge specific surface area and abundant unsaturated active sites,have emerged as versatile electrocatalysts for oxygen evolution reactions,and thus,great progress has been made in the rational design and synthesis of Co‐based nanomaterials for electrocatalytic oxygen evolution reactions.Considering the remarkable progress in this area,in this timely review,we highlight the most recent developments in Co‐based nanomaterials relating to their dimensional control,defect regulation(conductivity),electronic structure regulation,and so forth.Furthermore,a brief conclusion about recent progress achieved in oxygen evolution on Co‐based nanomaterials,as well as an outlook on future research challenges,is given.展开更多
Cobalt-based phosphides show excellent hydrogen evolution reaction(HER)performance,however,improving the intrinsic activity and stability of it in alkaline electrolyte still remains a challenge.Herein,CoRuOH/Co_(2)P/C...Cobalt-based phosphides show excellent hydrogen evolution reaction(HER)performance,however,improving the intrinsic activity and stability of it in alkaline electrolyte still remains a challenge.Herein,CoRuOH/Co_(2)P/CF with heterojunction structure was developed by means of molten salt and rapid hydrolysis(30 s).The OH-from rapid surface hydrolysis of Co_(2)P as a hydrogen adsorption site can facilitate the formation of thin CoRuOH layer as a water dissociation site,which may bring out better synergistic effect for alkaline HER.Moreover,the covering of CoRuOH can improve the stability of Co_(2)P for HER.When drives at 100 mA/cm^(2),it only requires overpotential of 81 mV in 1.0 mol/L KOH(25℃).Even at higher current density(1000 mA/cm^(2)),CoRuOH/Co_(2)P/CF can also operate stability for at least 100 h.When coupling with NiFe-LDH/IF in a two-electrode system,the voltage of NiFe-LDH/IF(+)||CoRuOH/Co_(2)P/CF(-)at 1000 mA/cm^(2)is merely 1.77 V with 100 h,demonstrating great potential for water splitting.The implementation of this work provides a new strategy and reference for the further improvement of transition metal phosphides as HER electrocatalysts.展开更多
基金supported by NSFC(Grant No.52202265,52302004,52472010,62434010)the Taishan Scholars Program of Shandong Province(tsqn202306330)+1 种基金Shenzhen Science and Technology Program(JCYJ20230807094009018)Xiaomi Young Talents Program(2023XM06).
文摘Gallium nitride(GaN)single crystal with prominent electron mobility and heat resistance have great potential in the high temperature integrate electric power systems.However,the sluggish charge storage kinetics and inadequate energy densities are bottlenecks to its practical application.Herein,the self-supported GaN/Mn_(3)O_(4) integrated electrode is developed for both energy harvesting and storage under the high temperature environment.The experimental and theoretical calculations results reveal that such integrated structures with Mn-N heterointerface bring abundant active sites and reconstruct low-energy barrier channels for efficient charge transferring,reasonably optimizing the ions adsorption ability and strengthening the structural stability.Consequently,the assembled GaN based supercapacitors deliver the power density of 34.0 mW cm^(-2) with capacitance retention of 81.3%after 10000 cycles at 130℃.This work innovatively correlates the centimeter scale GaN single crystal with ideal theoretical capacity Mn_(3)O_(4) and provides an effective avenue for the follow-up energy storage applications of the wide bandgap semiconductor.
文摘In recent years,numer-ous single-atom catalysts(SACs)have been synthesized to activate persulfate(PS)by a non-radical pathway because of its high se-lectivity,and activity for the cata-lyst.Metal-nitrogen-carbon(M-N_(x)-C)has been identified as the key active site in SACs.Although methods for preparing SACs have been extensively reported,a systematic summary of the direct construction of M-N_(x)-C,espe-cially unconventional metal-nitrogen-carbon(UM-N_(x)-C,x≠4),on SACs for PS non-radical activation has still not been reported.The role of the M-N_(x)-C active sites on PS non-radical activation is discussed and methods for the formation of M-N_(x)-C and UM-N_(x)-C active sites in SACs and the effect of catalyst carriers such as carbon nitride(g-C_(3)N_(4)),MOFs,COFs,and other car-bon materials are reviewed.Direct and indirect methods,especially for UM-N_(x)-C active site formation,are also elaborated.Factors affecting the formation of a M-N_(x)-C active site on SACs are also discussed.Prospects for the use of M-N_(x)-C active sites for the non-radical activation of PS by SACs to remove organic contaminants from wastewater are evaluated.
基金supported by Research Grant from China Petroleum and Chemical Corp。
文摘Cu/ZnO-based catalysts are widely employed for methanol synthesis via CO_(2) hydrogenation.The preparation procedure is sensitive to the particle size and interfacial structure,which are considered as potential active centers influencing the rate of both methanol and CO formation.The particle size and the interaction between Cu and the support materials are influenced by the coprecipitation conditions,let alone that the mechanistic divergence remains unclear.In this work,a series of Cu/ZnO/ZrO_(2) catalysts were prepared via co-precipitation at different pH value and systematically characterized.The structure has been correlated with kinetic results to establish the structure-performance relationship.Kinetic analysis demonstrates that methanol synthesis follows a single-site Langmuir-Hinshelwood(L-H)mechanism,i.e.,Cu serves as the active site where CO_(2) and H_(2) competitively adsorb and react to form methanol.In contrast,CO formation proceeds via a dual-site L-H mechanism,where CO_(2) adsorbs onto ZnO and H_(2) onto Cu,with the reaction occurring at the Cu/ZnO interface.Therefore,for the direct formation of methanol,solely reducing the particle size of Cu would not be beneficial.
文摘The quest for sustainable energy solutions has intensified the search for alternative feedstocks that can supplement or replace fossil fuels. Obtaining fuels or chemicals through the conversion of renewable biomass is a promising candidate [1,2]. Some noblemetal-based (e.g., Pt, Pd and Rh) catalysts exhibit significant catalytic activity to the conversion reaction of these biomass.
基金partially supported by the National Natural Science Foundation of China(Nos.22373092,22288201)CAS Project for Young Scientists in Basic Research(YSBR-051)+1 种基金Innovation Program for Quantum Science and Technology(2021ZD0303306)supported by University of Science and Technology of China Tang Scholarship and State Scholarship Fund(202206345005)。
文摘Single atom catalysts supported by two-dimensional(2D)materials,including graphene,g-C_(3)N_(4),and graphdiyne,ex-hibit promising electrocatalytic nitrogen reduction reaction(NRR)activity.Nevertheless,sometimes theoretical works failed to predict the high activity of NRR of single atom cat-alysts,especially for Fe,Co,Mn,Cu,Ru.In this work,based on DFT calculations,it is suggested that dual-atom sites on N doped graphene(M_(2)@N-graphene)rather than single-atom sites are more likely to be the active sites for NRR.Notably,Fe_(2)@N_(3),Co_(2)@N_(2),Mn_(2)@N_(2),Cu_(2)@N_(1),and Ru_(2)@N_(3)endow the best catalytic activity with corresponding limiting potentials of-0.26,-0.18,-0.17,-0.39,and-0.30 V,re-spectively.Furthermore,on g-C_(3)N_(4)and graphdiyne,triple-atom sites(TAS,M_(3))such as Ru_(3)(Co_(3))@g-C_(3)N_(4)and Ru_(3)(Rh_(3))@graphdiyne are expected to exhibit higher stability and NRR catalytic performance than single-atom sites(SAS)and dual-atom sites(DAS),with corresponding limiting potentials of-0.28,-0.48,-0.24,and-0.23 V.The calculated results with the corresponding experimental potentials indicate that the origin of superior NRR ac-tivity observed in experiments may be contributed by M_(2)or M_(3)on 2D materials.This study provides an in-depth investigation into real active NRR sites of metal atoms supported on 2D materials and contributes to the design of effective NRR catalysts.
基金supported by the National Natural Science Foundation of China(No.22378308)Jing-Jin-Ji Regional Integrated Environmental Improvement-National Science and Technology Major Project(No.2024ZD1200301–2)the Scientific and Technological Project of Yunnan Precious Metal Laboratory(No.YPML2023050202)。
文摘A comprehensive understanding of the structure and dynamic evolution of catalytic active sites is vital for advancing the study of liquid-phase acetylene hydrochlorination.Here,we successfully developed a Ru-DIPEA/TMS catalyst optimised through systematic composition and condition tuning,demonstrating exceptional performance with 95.5%C_(2)H_(2)conversion and sustaining over 91.1%activity along with nearly 100%selectivity for VCM during a continuous 900-h test.Using a combination of characterisation techniques,including UV–vis spectroscopy,FT-IR spectroscopy,X-ray photoelectron spectroscopy,singlecrystal X-ray diffraction,and X-ray absorption spectroscopy,along with density functional theory(DFT)calculations,the structure and dynamic behaviour of the active sites were thoroughly investigated under the synergistic influence of ligands and HCl.The results revealed that HCl activation induces a significant structural transformation of the active sites,leading to the formation of a hexacoordinate complex,Ru(CO)_(2)C_(12)(C_(6)H_(15)N·HCl)_(2).DFT calculations further elucidated the mechanism underlying active site formation,revealing that an increased electron density around the Ru centre and corresponding changes in its coordination environment play critical roles in enhancing catalyst stability and activity.This study contributes to a deeper understanding of the structural basis of active site evolution during acetylene hydrochlorination,offering both practical insights into industrial applications and foundational knowledge for advancing liquid-phase catalysis.
基金financially supported by the National Natural Science Foundation of China(Nos.22366004 and 42302293)the National Key Laboratory of Uranium Resources Exploration-Mining and Nuclear Remote Sensing Independent Project(No.2024QZ-TD-19)+2 种基金the Key R&D Plan of Jiangxi Province(No.20212BBG71011)China Uranium Corporation Limited-East China University of Technology State Key Laboratory of Nuclear Resources and Environment Joint Innovation Fund(No.2023NRE-LH-19)the Innovation Special Fund Project of Graduate Student in East China University of Technology(No.DHYC-202414)
文摘Urchin-like W_(18)O_(49),with a large specific surface area(113.738 m^(2)g^(-1))and abundant oxygen vacancies(OVs),was prepared using an active sites tuning and microstructure engineering method.This material was applied for U(Ⅵ)adsorption for the first time,demonstrating a high adsorption capacity of 567.55 mg g^(-1),which exceeds that of most inorganic adsorbents.Characterization via active site masking experiments and theoretical calculations,etc.,indicated that the excellent adsorption performance toward U(Ⅵ)was due to strong complexation between UO_(2)^(2+)and W–O bond of W_(18)O_(49),facile oxygen vacancy adsorption,and interface electron transfer from W^(5+)to UO_(2)^(2+),which acted as a reducing agent,partially converting U(Ⅵ)to U(IV).Furthermore,W_(18)O_(49)exhibited practical applicability with a removal rate exceeding 82%after 5 cycles,a 92.79%removal rate for real uranium-containing wastewater,and a high uranium recovery rate of 75.96%.Additionally,the synergistic adsorption-photocatalytic effect significantly enhanced U(Ⅵ)extraction,reaching an extraction capacity of 988.0mg g^(-1).This work provides a promising strategy for developing highly efficient U(Ⅵ)WO_(3)-based adsorbents.
基金supported by the National Natural Science Foundation of China(22008033)the Major Program of Qingyuan Innovation Laboratory.
文摘Efficient recognition and selective capture of NH_(3)is not only beneficial for increasing the productivity of the synthetic NH_(3)industry but also for reducing air pollution.For this purpose,a group of deep eutectic solvents(DESs)consisting of glycolic acid(GA)and phenol(PhOH)with low viscosities and multiple active sites was rationally designed in this work.Experimental results show that the GA^(+)PhOH DESs display extremely fast NH_(3)absorption rates(within 51 s for equilibrium)and high NH_(3)solubility.At 313.2 K,the NH_(3)absorption capacities of GA^(+)PhOH(1:1)reach 6.75 mol/kg(at 10.7 kPa)and 14.72 mol/kg(at 201.0 kPa).The NH_(3)solubility of GA^(+)PhOH DESs at low pressures were minimally changed after more than 100 days of air exposure.In addition,the NH_(3)solubility of GA^(+)PhOH DESs remain highly stable in 10 consecutive absorption-desorption cycles.More importantly,NH_(3)can be selectively captured by GA^(+)PhOH DESs from NH_(3)/CO_(2)/N_(2)and NH_(3)/N_(2)/H_(2)mixtures.1H-NMR,Fourier transform infrared and theoretical calculations were performed to reveal the intrinsic mechanism for the efficient recognition of NH_(3)by GA^(+)PhOH DESs.
文摘Electrocatalytic conversion of carbon dioxide(CO_(2))offers an effective method of CO_(2)fixation to mitigate global warming and the energy crisis.However,for supported Ni single-atom catalysts(SACs),which are among the most promising candidates for this application,the relationship between Ni coordination structure and catalytic properties is still under strong debate.Here,we fabricated a series of Ni SACs through precise-engineering of anchor sites on nitrogen-doped carbon(NC)followed by Ni atom anchoring using atomic layer deposition.Among them,a Ni_(1)/NC SAC,with a coordination number(CN)of four but less pyridinic nitrogen(N_(pyri)),achieved over 90%faradaic efϐiciency for CO at potentials from-0.7 to-1.0 V and a mass activity of 6.5 A/mgNi at-0.78 V along with high stability,outperforming other Ni SACs with lower CN and more N_(pyri).Theoretical calculations of various three and four-coordinated Ni_(1)-NxCy structures revealed a linear correlation between the reaction Gibbs free energy for the potential-limiting step and the highest occupied molecular orbital(HOMO)position of Ni-3d orbitals,therein the four-coordinated Ni_(1)-N_(1)C_(3)with the highest HOMO position is identified as the active site for the electrocatalytic CO_(2)-to-CO process,in line with the experimental results.
基金financially supported by National High-Level Talent FundNational Natural Science Foundation of China (Nos. 22372138,22461160253,22121001,and 22072118)+3 种基金thank financial support from State Key Laboratory of Physical Chemistry of Solid Surfaces of Xiamen UniversityShenzhen Science and Technology Program (No. JCYJ20220530143401002)supported by Science and Technology Projects of Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM) (No. HRTP-[2022]-3)the Fundamental Research Funds for the Central Universities (No. 20720220008)
文摘The electrochemical reduction of carbon dioxide(CO_(2)RR)is a promising strategy for achieving carbon neutralization.The Ni-N_(4) site is well known as the active site in metal single atoms on N-doped carbon catalysts,while its symmetric charge distribution nature is not favorable for electron transfer and then hindering the efficient CO_(2)RR.Herein,we constructed a Ni SA/CNs single-atom catalyst.Notably,it features unique Ni-N_(4)-O active sites,featuring one axial O atom and four planar N atoms,constituting a broken symmetrical electronic structure of Ni-N_(4) sites.Furthermore,hierarchical pore structures were obtained with the assistance of NaNO_(3) pore-forming agent during thermal treatment process,which promote electronic and mass transfer.And the resulting high specific surface area can host more Ni-N_(4)-O active sites.These specialized active sites promote the key intermediate(∗CO)adsorption/desorption and suppresses hydrogen evolution.Consequently,the Ni SA/CNs catalyst exhibits a high turnover frequency(TOF)value,reaching 34,081 h^(-1) at-0.98 V vs.RHE.Additionally,it achieves an excellent CO Faradaic efficiency,exceeding 90%,over a wide potential range from-0.4 V to-1.0 V vs.RHE.This work not only offers a new method for the rational synthesize single-atom catalysts with unique Ni-N_(4)-O active sites,but also provides in-depth insight into the origin of catalytic activity of porous carbon-base catalysts.
文摘Single-atom catalysts are promising for H_(2)O_(2) photosynthesis from O_(2) and H_(2)O,but their efficiency is still limited by the ill-defined electronic structure.In this study,Co single-atoms with unique four planar N-coordination and one axial P-coordination(Co-N_(4)P_(1))are decorated on the lateral edges of nanorod-like crystalline g-C_(3)N_(4)(CCN)photocatalysts.Significantly,the electronic structures of central Co as active sites for O_(2) reduction reaction(ORR)and planar N-coordinator as active sites for H_(2)O oxidation reaction(WOR)in Co-N_(4)P_(1) can be well regulated by the synergetic effects of introducing axial P-coordinator,in contrast to the decorated Co single-atoms with only four planar N-coordination(Co-N_(4)).Specifically,directional photoelectron accumulation at central Co active sites,induced by an introduced midgap level in Co-N_(4)P_(1),mediates the ORR active sites from 4e–-ORR-selective terminal–NH_(2) sites to 2e–-ORR-selective Co sites,moreover,an elevated d-band center of Co 3d orbital strengthens ORR intermediate*OOH adsorption,thus jointly facilitating a highly selective and active 2e^(–)-ORR pathway to H_(2)O_(2) photosynthesis.Simultaneously,a downshifted p-band center of N_(2)p orbital in Co-N_(4)P_(1) weakens WOR intermediate*OH adsorption,thus enabling a preferable 2e^(–)-WOR pathway toward H_(2)O_(2) photosynthesis.Subsequently,Co-N_(4)P_(1) exhibits exceptional H_(2)O_(2) photosynthesis efficiency,reaching 295.6μmol g^(-1) h^(-1) with a remarkable solar-to-chemical conversion efficiency of 0.32%,which is 15 times that of Co-N_(4)(19.2μmol g^(-1) h^(-1))and 10 times higher than CCN(27.6μmol g^(-1) h^(-1)).This electronic structure modulation on single-atom catalysts offers a promising strategy for boosting the activity and selectivity of H_(2)O_(2) photosynthesis.
基金This work was supported by the National Natural Science Foundation of China(Nos.22138011,22205108,22378206)Open Research Fund of Key Laboratory of the Ministry of Education for Advanced Catalysis Materials and Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces(KLMEACM 202201),Zhejiang Normal University.
文摘The insufficient active sites and slow interfacial charge trans-fer of photocatalysts restrict the efficiency of CO_(2) photoreduction.The synchronized modulation of the above key issues is demanding and chal-lenging.Herein,strain-induced strategy is developed to construct the Bi–O-bonded interface in Cu porphyrin-based monoatomic layer(PML-Cu)and Bi_(12)O_(17)Br_(2)(BOB),which triggers the surface interface dual polarization of PML-Cu/BOB(PBOB).In this multi-step polarization,the built-in electric field formed between the interfaces induces the electron transfer from con-duction band(CB)of BOB to CB of PML-Cu and suppresses its reverse migration.Moreover,the surface polarization of PML-Cu further promotes the electron converge in Cu atoms.The introduction of PML-Cu endows a high density of dispersed Cu active sites on the surface of PBOB,significantly promoting the adsorption and activation of CO_(2) and CO desorption.The conversion rate of CO_(2) photoreduction to CO for PBOB can reach 584.3μmol g-1,which is 7.83 times higher than BOB and 20.01 times than PML-Cu.This work offers valuable insights into multi-step polarization regulation and active site design for catalysts.
基金supported by the National Natural Science Foundation of China(22221005 and 22008033).
文摘The efficient separation and collection of ammonia(NH_(3))during NH_(3) synthesis process is essential to improve the economic efficiency and protect the environment.In this work,ethanolammonium hydrochloride(EtOHACl)and phenol(PhOH)were used to prepare a novel class of deep eutectic solvents(DESs)with multiple active sites and low viscosities.The NH_(3) separation performance of EtOHACl+PhOH DESs was analyzed completely.It is figured out that the NH_(3) absorption rates in EtOHACl+PhOH DESs are very fast.The NH_(3) absorption capacities are very high and reach up to 5.52 and 10.74 mol·kg1 at 11.2 and 100.4 kPa under 298.2 K,respectively.In addition,the EtOHACl+PhOH DESs present highly selective absorption of NH_(3) over N_(2) and H_(2) and good regenerative properties after seven cycles of absorption/desorption.The intrinsic separation mechanism of NH_(3) by EtOHACl+PhOH DESs was further revealed by spectroscopic analysis and quantum chemistry calculations.
基金supported by the National Natural Science Foundation of China (No.21908049,52274298,and 51974114)Hunan Provincial Natural Science Foundation of China (No.2022JJ40035,2020JJ4175,2024JJ4022,2023JJ30277)+2 种基金Science and Technology Talents Lifting Project of Hunan Province (No.2022TJ-N16)Open Fund of State Key Laboratory of Advanced Metallurgy,University of Science and Technology Beijing (K1:24-09)Postdoctoral Fellowship Program (No.GZC20233205)。
文摘Though Zn-air batteries(ZABs)are one of the most promising system for energy storage and conversion,challenge still persists in its commercial application due to the sluggish kinetics of oxygen reduction/evolution reaction(ORR/OER).Hereby,a polyvinylidene fluoride(PVDF)-assisted pyrolysis strategy is proposed to develop a novel corrugated plate-like bifunctional electrocatalyst using two-dimensional zeolitic imidazolate frameworks(2D ZIF-67)as the precursor.The employed PVDF plays an important role in inheriting the original 2D structure of ZIF-67 and modulating the composition of the final products.As a result,a corrugated plate-like electrocatalyst,high-density Co nanoparticles decorated 2D Co,N,and F tri-doped carbon nanosheets,can be obtained.The acquired electrocatalyst enables efficient active sites and rapid mass transfer simultaneously,thus showing appreciable electrocatalytic performance for rechargeable Zn-air batteries.Undoubtedly,our proposed strategy offers a new perspective to the design of advanced oxygen electrocatalysts.
基金financially supported by the National Natural Science Foundation of China(Nos.52002361 and 22109120)the Science and Technology Research Project of Jiangxi Provincial Education Department(Nos.GJJ2201045 and GJJ2201007)+2 种基金Zhejiang Provincial Natural Science Foundation of China(No.LQ21B030002)the Key Project for Science and Technology Cooperation of Jiangxi Province(No.20212BDH80005)the Project of the Science and Technology of Jingdezhen City(No.20202GYZD013-16)。
文摘Given the clean and inexhaustible solar energy from solar light,photocatalytic ammonia synthesis is extremely appealing.However,high electron-hole recombination rates and insufficient active sites severely limited N2 photoreaction reduction.Herein,we designed and fabricated FeCu alloy nanoparticles anchored on carbon nitride nanosheets with excellent photocatalyt ic ammonia synthesis performance.As a coupler between Fe and carbon nitride,Cu promotes the separation of photogenerated charge carriers in carbon nitride under solar light irradiation,and renters the semiconductor a forceful electron donor for the Fe active sites.The accumulated electrons at Fe sites furtherly facilitated the adsorption and activation of the molecular nitrogen.Besides,the uniform dispersed FeCu alloy nanoparticles were on carbon nitride nanosheets enhanced the stability of photocataly tic nitrogen reduction reaction,making the artificial photocataly tic ammonia synthesis more sustainable for application.This work highlights that a direct electron transfer channel can be used to regulate the photochemical nitrogen fixation network.
基金supported by the National Key R&D Program of China(No.2021YFA1500900)the National Natural Science Foundation of China(Nos.22102053,21825201,22172047 and U19A2017)+7 种基金the Provincial Natural Science Foundation of Hunan(Nos.2019GK2031,2016TP1009,2020JJ5045 and 2021JJ30089)the Science and Technology Innovation Program of Hunan Province,China(Nos.2020RC2020,2022RC1036)Shenzhen Science and Technology Program(No.JCYJ20210324122209025)Basic and Applied Basic Research Foundation of Guangdong Province-Regional joint fund project(No.2021B1515120024)Natural Science Foundation of Chongqing(No.cstc2021jcyj-msxmX0770)the Science Funds of the Education Office of Jiangxi Province(No.GJJ2201324)the Science Funds of Jiangxi Province(No.20224BAB213018)the China Postdoctoral Science Foundation(Certificate No.2023M741121)。
文摘In electrochemical energy devices,the operating conditions always exert enormous influence on electrocatalysts'performances.Phosphoric acid(PA),acted as the proton carriers,can be adsorbed on Pt surface,block active sites and affect the electronic structure of Pt unfavorably,which severely restricts the performance of high-temperature proton exchange membrane fuel cells(HT-PEMFCs).Herein,simply basic organic compounds,such as dicyandiamide(DCD),melamine(Mel)and cyanuric acid(CA),are decorated on Pt surface(DCD-Pt/C,Mel-Pt/C and CA-Pt/C)to induce the adsorption transfer of proton carriers.The decoration can not only inject electrons to Pt and enhance oxygen reduction reaction(ORR)activity but also can induce PA to transfer from Pt surface to organic compounds,decontaminating active sites.In addition,the organic compounds with the larger conjugated system and the smaller electronegativity of ligating atoms would have a greater interaction with Pt,causing a larger decoration amount on Pt surface,which leads to more excellent ORR activity and resistance to PA blockage effect.Therefore,MelPt/C shows a peak power density of 629 mW/cm^(2),exceeding commercial Pt/C(437 mW/cm^(2)),DCD-Pt/C(539 m W/cm^(2))and CA-Pt/C(511 mW/cm^(2))with the same loading.
基金supported from Science Fund for Distinguished Young Scholars of Nanjing Forestry University(No.JC2019002)。
文摘Constructing synergistic active sites and optimizing the cooperative adsorption energies for hydrogen and hydroxyl based intermediates are two essential strategies to improve the sluggish kinetics of hydrogen evolution reaction(HER)in alkaline medium.However,it is still in its infancy to simultaneously achieve these goals,especially for designing a well-defined carrier with multiple hydroxyl adsorption sites.Herein,the Ni(HCO_(3))_(2)nanoplates(NHC)with horizontal interfaces sites of Ni-terminated NiO,NiOOH,NiCOO,and Ni(OH)_(2)were employed as the hydroxyl adsorption active sites,which could anchor Pt particles with hydrogen adsorption active sites,constructing the synergistic active sites(NHC-Pt)for HER catalysis.Evidenced by X-ray photoelectron spectroscopy(XPS)and extended X-ray absorption fine structure(EXAFS),the NHC could affect the chemical state and electronic structure of Pt particles by forming bond of Pt-O which could reduce the reaction energy barriers,facilitate the adsorption of hydrogen and establishment of H–H bond.Furthermore,density functional theory(DFT)theoretical calculation revealed that the related process of hydroxide was the rate-determining step.It is demonstrated the hydroxyl group presents the lowest energy barrier for desorption in the process of HER when the gradual desorption process could be described as a migration from Ni(HCO_(3))_(2)·OH directly or via other Ni-based systems formed after partial decomposition of nickel hydrocarbonate to Ni(OH)_(2)…OH with following desorption.As a result,the NHC-Pt hierarchical nanostructure demonstrated superior activity towards HER in a pH-universal solution.This enhancement can be attributed to the optimized electronic structure of Pt,the migration of hydroxyl group on NHC substrates,and the synergistic effects between the NHC carrier and Pt particles.
基金financially supported by the National Natural Science Foundation of China with grant number of 22172082 and 21978137。
文摘The development of earth-abundant electrocatalysts with high performance for electrochemical CO_(2)reduction(ECR)is of great significance.Cu-based catalysts have been widely investigated for ECR due to their unique ability to generate various carbonaceous products,but directing selectivity toward one certain product and identifying the real active sites during ECR are still full of challenge.Here,after the incorporation of CdO into CuO,the Cu_(0.5)Cd_(0.5)-O catalyst achieves a 10.3-fold enhancement for CO selectivity in comparison with CuO,and a CO faradic efficiency nearly 90%with a current density around20 mA cm^(-2)could maintain at least 60 h.Interestingly,a wide CO/H_(2)ratio(0.07-10)is reached on Cu_(x)Cd_(1-x)-O catalysts by varying the Cu/Cd ratio,demonstrating the potential of syngas production using such catalysts.The results of ex situ XRD,XPS,and in situ Raman reveal that the real active sites of Cu_(0.5)Cd_(0.5)-O catalysts for CO production during ECR reaction are the reconstructed mixed phases of CuCd alloy and CdCO_(3).In situ FTIR and theoretical calculations further implicate the presence of Cd related species promotes the CO desorption and inhibits the H_(2)evolution,thus leading to an enhanced CO generation.
基金National Natural Science Foundation of China,Grant/Award Number:22172063Young Taishan Scholars Program,Grant/Award Number:tsqn201812080+1 种基金China Scholarship Council(CSC),Grant/Award Number:202008130132Independent Cultivation Program of Innovation Team of Ji'nan City,Grant/Award Number:2021GXRC052。
文摘Electrocatalytic water splitting has been identified as a potential candidate for producing clean hydrogen energy with zero carbon emission.However,the sluggish kinetics of oxygen evolution reaction on the anode side of the watersplitting device significantly hinders its practical applications.Generally,the efficiency of oxygen evolution processes depends greatly on the availability of cost‐effective catalysts with high activity and selectivity.In recent years,extensive theoretical and experimental studies have demonstrated that cobalt(Co)‐based nanomaterials,especially low‐dimensional Co‐based nanomaterials with a huge specific surface area and abundant unsaturated active sites,have emerged as versatile electrocatalysts for oxygen evolution reactions,and thus,great progress has been made in the rational design and synthesis of Co‐based nanomaterials for electrocatalytic oxygen evolution reactions.Considering the remarkable progress in this area,in this timely review,we highlight the most recent developments in Co‐based nanomaterials relating to their dimensional control,defect regulation(conductivity),electronic structure regulation,and so forth.Furthermore,a brief conclusion about recent progress achieved in oxygen evolution on Co‐based nanomaterials,as well as an outlook on future research challenges,is given.
基金financially supported by the National Natural Science Foundation of China(Nos.52174283 and 52274308)。
文摘Cobalt-based phosphides show excellent hydrogen evolution reaction(HER)performance,however,improving the intrinsic activity and stability of it in alkaline electrolyte still remains a challenge.Herein,CoRuOH/Co_(2)P/CF with heterojunction structure was developed by means of molten salt and rapid hydrolysis(30 s).The OH-from rapid surface hydrolysis of Co_(2)P as a hydrogen adsorption site can facilitate the formation of thin CoRuOH layer as a water dissociation site,which may bring out better synergistic effect for alkaline HER.Moreover,the covering of CoRuOH can improve the stability of Co_(2)P for HER.When drives at 100 mA/cm^(2),it only requires overpotential of 81 mV in 1.0 mol/L KOH(25℃).Even at higher current density(1000 mA/cm^(2)),CoRuOH/Co_(2)P/CF can also operate stability for at least 100 h.When coupling with NiFe-LDH/IF in a two-electrode system,the voltage of NiFe-LDH/IF(+)||CoRuOH/Co_(2)P/CF(-)at 1000 mA/cm^(2)is merely 1.77 V with 100 h,demonstrating great potential for water splitting.The implementation of this work provides a new strategy and reference for the further improvement of transition metal phosphides as HER electrocatalysts.
