Effectively controlling the selectivity of C_(2) oxygenates is desirable for electrocatalytic CO_(2) reduction.Copper catalyst has been considered as the most potential for reducing CO_(2) to C_(2) products,but it sti...Effectively controlling the selectivity of C_(2) oxygenates is desirable for electrocatalytic CO_(2) reduction.Copper catalyst has been considered as the most potential for reducing CO_(2) to C_(2) products,but it still suffers from low C_(2) selectivity,high overpotential,and competitive hydrogen evolution reaction(HER).Here,we propose a design strategy to introduce a second metal that weakly binds to H and a functional ligand that provides hydrogen bonds and protons to achieve high selectivity of C_(2)oxygenates and effective suppression of HER on the Cu(100)surface simultaneously.Seven metals and eleven ligands are screened using first-principles calculations,which shows that Sn is the most efficient for inhibiting HER and cysteamine(CYS)ligand is the most significant in reducing the limiting potential of^(*)CO hydrogenation to^(*)CHO.In the post C-C coupling steps,a so-called“pulling effect”that transfers H in the CYS ligand as a viable proton donor to the C_(2)intermediate to form an H bond,can further stabilize the OH group and facilitate the selection of C_(2)products toward oxygenates.Therefore,this heterogeneous electrocatalyst can effectively reduce CO_(2)to ethanol and ethylene glycol with an ultra-low limiting potential of-0.43 V.This study provides a new strategy for effectively improving the selectivity of C_(2)oxygenates and inhibiting HER to achieve advanced electrocatalytic CO_(2)reduction.展开更多
Surface properties （viz. surface area, basicity/base strength distribution, and crystal phases） of alkali metal doped CaO （alkali metal/Ca= 0.1 and 0.4） catalysts and their catalytic activity/selectivity in oxidat...Surface properties （viz. surface area, basicity/base strength distribution, and crystal phases） of alkali metal doped CaO （alkali metal/Ca= 0.1 and 0.4） catalysts and their catalytic activity/selectivity in oxidative coupling of methane （OCM） to higher hydrocarbons at different reaction conditions （viz. temperature, 700 and 750 ℃; CH4/O2 ratio, 4.0 and 8.0 and space velocity, 5140-20550 cm^3 ·g^-1·h^-1） have been investigated. The influence of catalyst calcination temperature on the activity/selectivity has also been investigated. The surface properties （viz. surface area, basicity/base strength distribution） and catalytic activity/selectivity of the alkali metal doped CaO catalysts are strongly influenced by the alkali metal promoter and its concentration in the alkali metal doped CaO catalysts. An addition of alkali metal promoter to CaO results in a large decrease in the surface area but a large increase in the surface basicity （strong basic sites） and the C2＋ selectivity and yield of the catalysts in the OCM process. The activity and selectivity are strongly influenced by the catalyst calcination temperature. No direct relationship between surface basicity and catalytic activity/selectivity has been observed. Among the alkali metal doped CaO catalysts, Na-CaO （Na/Ca = 0.1, before calcination） catalyst （calcined at 750 ℃）, showed best performance （C2＋ selectivity of 68.8% with 24.7% methane conversion）, whereas the poorest performance was shown by the Rb-CaO catalyst in the OCM process.展开更多
W_(18)O_(49)is a promising multifunctional material for electrochromic energy storage applications,owing to its abundant oxygen vacancies and distinctive crystalline structure.However,the contradiction between the hig...W_(18)O_(49)is a promising multifunctional material for electrochromic energy storage applications,owing to its abundant oxygen vacancies and distinctive crystalline structure.However,the contradiction between the high transmittance modulation for electrochromism and the high material loading for energy storage severely restricts the development of W_(18)O_(49)in multifunctional smart windows.This work found that different metal doping(Mo,Ti,Fe)exhibited significant differences in regulating the electrochromic performance and energy storage of W_(18)O_(49).And the oxygen vacancies of W_(18)O_(49)can be further controlled by adjusting the metal doping concentration,simultaneously achieving excellent electrochromic properties and energy storage.5%Ti-doped W_(18)O_(49)not only exhibits a high transmittance modulation of 82.3%(633 nm)and 81.0%(1050 nm)with fast coloration/bleaching times of 9.8/5.8 and 3.8/5.8 s,but also shows a good energy storage of 32.5 mF·cm^(-2)at 0.1 mA·cm^(-2).Theoretical calculations indicate Ti doped W_(18)O_(49)shows a more delocalized characteristic in band decomposition charge densities and a lower diffusion energy barrier,which is conducive to enhancing the electrochemical performance.This work demonstrates metal doping plays a significant role in simultaneously regulating electrochromism and energy storage,providing a new perspective for the development of multifunctional electrochromic materials.展开更多
As for the high sustainable solar hydrogen production via water splitting,transition metal doping on an oxide photoanode in photoelectrochemical(PEC)cells has been recognized as an effective approach.However,conventio...As for the high sustainable solar hydrogen production via water splitting,transition metal doping on an oxide photoanode in photoelectrochemical(PEC)cells has been recognized as an effective approach.However,conventional thermal-diffusionmediated doping strategies face the challenge of resolving sluggish catalytic kinetics for oxygen evolution reaction(OER)and its practical utilization for the synthesis of photoanode films.Herein,we introduce facile ultrafast flame-boosted doping of Mo into a BiVO_(4)(FL MoBVO)film for 20 s to achieve an efficient PEC OER.Mo elements in a low-valence state(i.e.,Mo^(6−δ))and Mo^(6+)are successfully doped into the photoanode,which manipulate the energy band structure,facilitating the downward shift of band edges and promoting the surface catalytic kinetics.Consequently,the flame-boosted Mo-doping results in superior PEC performance in a mild environment with neutral electrolyte without introducing any other additives or co-catalysts,where the photocurrent density at 1.23 V_(RHE) under 1 sun illumination in pH 7 is outstandingly enhanced,over 9-fold higher than that of a pristine BiVO_(4).The flame-boosted doping induces significantly enhanced photoexcited charge transport and catalytic reaction kinetics performances simultaneously.Our report provides the effective strategy boosting both the thermodynamic and kinetic charge migration properties for sustainable materials.展开更多
Durable and inexpensive graphitic carbon nitride(g-C_(3)N_(4))demonstrates great potential for achieving efficient photocatalytic hydrogen evolution reduction(HER).To further improve its activity,g-C_(3)N_(4)was subje...Durable and inexpensive graphitic carbon nitride(g-C_(3)N_(4))demonstrates great potential for achieving efficient photocatalytic hydrogen evolution reduction(HER).To further improve its activity,g-C_(3)N_(4)was subjected to atomic-level structural engineering by doping with transition metals(M=Fe,Co,or Ni),which simultaneously induced the formation of metal-N active sites in the g-C_(3)N_(4)framework and modulated the bandgap of g-C_(3)N_(4).Experiments and density functional theory calculations further verified that the as-formed metal-N bonds in M-doped g-C_(3)N_(4)acted as an"electron transfer bridge",where the migration of photo-generated electrons along the bridge enhanced the efficiency of separation of the photogenerated charges,and the optimized bandgap of g-C_(3)N_(4)afforded stronger reduction ability and wider light absorption.As a result,doping with either Fe,Co,or Ni had a positive effect on the HER activity,where Co-doped g-C_(3)N_(4)exhibited the highest performance.The findings illustrate that this atomic-level structural engineering could efficiently improve the HER activity and inspire the design of powerful photocatalysts.展开更多
Nano-diamond particles are co-deposited on Ti substrates with metal(Ti/Ni) nanoparticles(NPs) by the electrophoretic deposition(EPD) method combined with a furnace annealing at 800℃ under N_(2) atmosphere. Modificati...Nano-diamond particles are co-deposited on Ti substrates with metal(Ti/Ni) nanoparticles(NPs) by the electrophoretic deposition(EPD) method combined with a furnace annealing at 800℃ under N_(2) atmosphere. Modifications of structural and electron field emission(EFE) properties of the metal-doped films are investigated with different metal NPs concentrations. Our results show that the surface characteristics and EFE performances of the samples are first enhanced and then reduced with metal NPs concentration increasing. Both the Ti-doped and Ni-doped nano-diamond composite films exhibit optimal EFE and microstructural performances when the doping quantity is 5 mg. Remarkably enhanced EFE properties with a low turn-on field of 1.38 V/μm and a high current density of 1.32 mA/cm^(2) at an applied field of 2.94 V/μm are achieved for Ni-doped nano-diamond films, and are superior to those for Ti-doped ones. The enhancement of the EFE properties for the Ti-doped films results from the formation of the TiC-network after annealing. However, the doping of electron-rich Ni NPs and formation of high conductive graphitic phase are considered to be the factor, which results in marvelous EFE properties for these Ni-doped nano-diamond films.展开更多
The utilization of visible light for photocatalytic nitrogen fixation offers a sustainable and eco-friendly strategy for the production of ammonia.The present study focuses on the synthesis of a series of rare earth-d...The utilization of visible light for photocatalytic nitrogen fixation offers a sustainable and eco-friendly strategy for the production of ammonia.The present study focuses on the synthesis of a series of rare earth-doped carbon nitride composite ultraviolet-activated Ce-UiO-66 catalysts,denoted as RECNactMOF,for efficient nitrogen fixation.Rare earth doping modulates the band structure of carbon nitride,facilitating the formation of a type-I heterojunction with Ce-UiO-66 and promoting photocarrier generation at nitrogen fixation sites.Among these,Sm-doped SmCN-actMOF exhibits high visible-light absorption and efficient utilization of photocarriers,resulting in an apparent quantum efficiency(AQE)of 1.58%under 495 nm light irradiation.This study provides a pathway for enhancing the nitrogen fixation efficiency of photocatalysts through the incorporation of rare earth elements,and expanding the potential applications of rare earth materials in the field of photocatalysis.展开更多
Hydrogen evolution reaction(HER)in acidic media has been spotlighted for hydrogen production since it is a favourable kinetics with the supplied protons from a counterpart compared to that within alkaline environment....Hydrogen evolution reaction(HER)in acidic media has been spotlighted for hydrogen production since it is a favourable kinetics with the supplied protons from a counterpart compared to that within alkaline environment.However,there is no choice but to use a platinum-based catalyst yet.As for a noble metal-free electrocatalyst,incorporation of earth-abundant transition metal(TM)atoms into nanocarbon platforms has been extensively adopted.Although a data-driven methodology facilitates the rational design of TM-anchored carbon catalysts,its practical application suffers from either a simplified theoretical model or the prohibitive cost and complexity of experimental data generation.Herein,an effective and facile catalyst design strategy is proposed based on machine learning(ML)and its model verification using electrochemical methods accompanied by density functional theory simulations.Based on a Bayesian genetic algorithm ML model,the Ni-incorporated carbon quantum dots(Ni@CQD)loaded on a three-dimensional reduced graphene oxide conductor are proposed as the best HER catalyst amongst the various TM-incorporated CQDs under the optimal conditions of catalyst loading,electrode type,and temperature and pH of electrolyte.The ML results are validated with electrochemical experiments,where the Ni@CQD catalyst exhibited superior HER activity,requiring an overpotential of 151 mV to achieve 10 mAcm^(−2) with a Tafel slope of 52 mV dec^(−1) and impressive durability in acidic media up to 100 h.This methodology can provide an effective route for the rational design of highly active electrocatalysts for commercial applications.展开更多
Due to its high electrical conductivity and platinum-like electronic structure,molybdenum phosphide(MoP)has attracted extensive attention as a potential catalyst for the hydrogen evolution reaction(HER)by water splitt...Due to its high electrical conductivity and platinum-like electronic structure,molybdenum phosphide(MoP)has attracted extensive attention as a potential catalyst for the hydrogen evolution reaction(HER)by water splitting.Nevertheless,in the oxygen evolution reaction(OER),the electrocatalytic performance of MoP did not achieve satisfactory results.Therefore,novel nitrogen-doped carbon-encapsulated Ladoped MoP nanoparticles(La-MoP@N/C)are synthesized,which show outstanding durability and electrocatalytic activity in both HER and OER.Detailed structural characterization and calculations confirm that La doping not only effectively adjusts the electron density around Mo and P atoms,accelerates the adsorption and desorption processes,but also increases the number of active sites.Low overpotentials of 113 and 388 mV for HER and OER at 10 mA cm−2 are achieved with the optimized La0.025-Mo0.975P@N/C.Furthermore,the two-electrode electrolyzer assembled with La0.025-Mo0.975P@N/C also presents impressive water splitting performance.This study indicates that rare earth doping can be used as an efficient strategy to control the local electronic structure of phosphides precisely,which can also be extended to other electrocatalysts.展开更多
Alloying with transition metal elements akin to Sm(CoFeCuZr)z can effectively enhance the magnetic properties of SmCo-based permanent magnets.However,the effects of transition metals doping on its magnetic properties,...Alloying with transition metal elements akin to Sm(CoFeCuZr)z can effectively enhance the magnetic properties of SmCo-based permanent magnets.However,the effects of transition metals doping on its magnetic properties,detailed atomic occupancy and the mechanism for structural stability remain unclear.Specifically,for SmCo3 magnets,there is minimal theoretical study available.Herein,based on first-principles calculations,we systematically investigated the influence of 3d transition metals(TMs)doping on the structural stability,magnetic properties and electronic characteristics of SmCo3 magnets.Our results show that Sc,Ti,V,Fe,Ni,Cu and Zn preferentially occupy the 18h lattice site,while Cr and Mn occupy the 3b and 6c lattice sites,respectively.Doping with Ti,Cr,Mn,Fe,Ni,Cu and Zn contributes to enhancing the stability of SmCo3,whereas the doping of Sc and V adversely affects structural stability.The magnetic calculations reveal that Cr,Mn and Fe doping significantly enhances the total magnetic moment.It is also found that lower concentrations of Cr doping can significantly enhance the magnetocrystalline anisotropy energy(MAE).More intriguingly,when the doping concentrations of Sc,Ni and Cu reach 14.81 at%,22.22 at%and 22.22 at%,respectively,the magnetic easy axis of the system shifts from out-of-plane to in-plane.The optimal doping concentration of Fe in the SmCo_(3) system is determined to be 37.04 at%.The Curie temperature of pure SmCo_(3) is 483.9 K.Our theoretical study offers valuable theoretical guidance for experimental exploration toward SmCo-based permanent magnets with higher performance.展开更多
Transition metal-doped CeO_(2)catalysts exhibit great potentials for the selective catalytic reduction(SCR)of nitrogen oxide(NOx)with NH_(3)(NH_(3)-SCR).However,traditional research mainly relies on a lot of experimen...Transition metal-doped CeO_(2)catalysts exhibit great potentials for the selective catalytic reduction(SCR)of nitrogen oxide(NOx)with NH_(3)(NH_(3)-SCR).However,traditional research mainly relies on a lot of experiments to find out effective catalysts,which wastes a lot of time and resources.Screening out effective CeO_(2)-based catalysts for low-temperature NH_(3)-SCR via density functional theory(DFT)calculations is crucial for the rational design and synthesis of efficient catalysts.Herein,transition metal(M=Co,Cr,Cu,Fe,Mn,Mo,Nb,Ni,Ta,Ti,V,and W)-doped CeO_(2)catalysts were screened out via accelerated DFT calculations for NH_(3)-SCR of nitric-oxide(NO)using three theoretical terms;(i)an adsorption energy of NH_(3),(ii)an adsorption energy of NO,and(iii)the reaction energies between NO with O_(2)and lattice oxygen.The theoretically predicted trend in catalytic performance is as follows:CeO_(2)-Mn,-Cu,-Mo>CeO_(2)-Fe,-Co,-Ni,-V,-Cr>CeO_(2)-W,-Ti>CeO_(2)-Nb,-Ta.The theoretical prediction was well verified via experimental NH_(3)-SCR activity of NO at low temperatures(90–300℃),demonstrating CeO_(2)-Mo as efficient NH_(3)-SCR catalyst across a broad temperature range.Temperature-programmed desorption of NH_(3)and in situ diffuse reflectance infrared Fourier transforms spectroscopy further indicated that metal doping significantly enhanced the NH_(3)adsorption capacity and strength of CeO_(2)in the medium-to low-temperature range.Consequently,accelerated DFT calculations provide a useful tool with great potentials for predicting the catalytic performance.展开更多
Metal-organic frameworks （MOFs） have attracted much attention as adsorbents for the separation of CO2 from flue gas or natural gas. Here, a typical metal-organic framework HKUST-I（also named Cu-BTC or MOF-199） was...Metal-organic frameworks （MOFs） have attracted much attention as adsorbents for the separation of CO2 from flue gas or natural gas. Here, a typical metal-organic framework HKUST-I（also named Cu-BTC or MOF-199） was chemically reduced by doping it with alkali metals （Li, Na and K） and they were further used to investigate their CO2 adsorption capacities. The structural information, surface chemistry and thermal behavior of the prepared adsorbent samples were characterized by X-ray powder diffraction （XRD）, thermo-gravimetric analysis （TGA） and nitrogen adsorption-desorption isotherm analysis. The results showed that the CO2 storage capacity of HKUST-1 doped with moderate quantities of Li＋, Na＋ and K＋, individually, was greater than that of unmodified HKUST-1. The highest CO2 adsorption uptake of 8.64 mmol/g was obtained with 1K-HKUST-1, and it was ca. 11% increase in adsorption capacity at 298 K and 18 bar as compared with HKUST- 1. Moreover, adsorption tests showed that HKUST-1 and 1K-HKUST-1 displayed much higher adsorption capacities of CO2 than those of N2. Finally, the adsorption/desorption cycle experiment revealed that the adsorption performance of 1K-HKUST-1 was fairly stable, without obvious deterioration in the adsorption capacity of CO2 after 10 cycles.展开更多
A series of transition metals(Fe,Co,Ni,Cu,Cr and Mn)-doped CeO_(2)-TiO_(2) catalysts were prepared by the sol-gel method and applied for the catalytic removal of 1,2-dichloroethane(DCE) as a model for chlorinated VOCs...A series of transition metals(Fe,Co,Ni,Cu,Cr and Mn)-doped CeO_(2)-TiO_(2) catalysts were prepared by the sol-gel method and applied for the catalytic removal of 1,2-dichloroethane(DCE) as a model for chlorinated VOCs(CVOCs).The various characterization methods including X-ray diffraction(XRD),N_(2) adsorption-desorption,UV-Raman,NH_(3) temperature-programmed desorption(NH_(3)-TPD) and H_(2) temperature-programmed reduction(H_(2)-TPR) were utilized to investigate the physicochemical properties of the catalysts.The results show that doping Fe,Co,Ni or Mn can obviously promote the activity of CeO_(2)-TiO_(2) mixed oxides for DCE degradation,which is related to their improved texture properties,acid sites(especially for strong acidity) and low-temperature reducibility.Particularly,CeTi-Fe doped with moderate Fe exhibits excellent activity for 1,2-dichloroethane(DCE) degradation,giving a T_(90%) value as low as 250℃.More importantly,only trace chlorinated byproducts were produced during the low-temperature degradation of various CVOCs(dichloromethane(DCM),trichloroethylene(TCE) and chlorobenzene(CB)) over CeTi-Fe1/9 catalyst with high durability.展开更多
The doping effects of transition metals(TMs = Mn, Co, Ni, and Cu) on the superconducting critical parameters are investigated in the films of iron selenide(Li,Fe)OHFe Se. The samples are grown via a matrix-assisted hy...The doping effects of transition metals(TMs = Mn, Co, Ni, and Cu) on the superconducting critical parameters are investigated in the films of iron selenide(Li,Fe)OHFe Se. The samples are grown via a matrix-assisted hydrothermal epitaxy method. Among the TMs, the elements of Mn and Co adjacent to Fe are observed to be incorporated into the crystal lattice more easily. It is suggested that the doped TMs mainly occupy the iron sites of the intercalated(Li,Fe)OH layers rather than those of the superconducting Fe Se layers. We find that the critical current density J_(c) can be enhanced much more strongly by the Mn dopant than the other TMs, while the critical temperature T_(c) is weakly affected by the TM doping.展开更多
The influence of transition metals(Sc,Ti,V,Cr,and Mn)doping at different distances on the magnetism of CdS is studied by using generalized gradient approximation combined with Hubbard U in the VASP package.The results...The influence of transition metals(Sc,Ti,V,Cr,and Mn)doping at different distances on the magnetism of CdS is studied by using generalized gradient approximation combined with Hubbard U in the VASP package.The results show that the doping systems are more stable,easy to form,and the wurtzite structure of CdS is not changed.It is found that the systems are antiferromagnetic(AFM)when nearest neighbor doping,which is attributed to the direct charge transfers between two impurity ions.The systems are ferromagnetic(FM)when the doping distance increases further,since the double exchange interactions are observed among the 3d orbital of the transition metal,the Cd-5s and the S-3p orbitals are at conduction band minimum.We also found that the total magnetic moment of each ferromagnetic system increases with the order of SC to Mn-doping,the spin polarizability of Cr-doping system is 100%.The estimated Curie temperature indicates that the Cr-and Mn-doped CdS in this paper can achieve room-temperature ferromagnetic characteristics,especially the Cr doping is the most prominent.And TM-doping does not destroy the semiconductor characteristics of the system.Therefore,the TM-doped CdS can be used as an ideal dilute magnetic semiconductor functional material.展开更多
Given the safety concerns and low energy density induced by liquid electrolytes,the interest in solidstate lithium metal batteries is rapidly growing.Among various solid electrolytes,garnet-type lithium lanthanum zirc...Given the safety concerns and low energy density induced by liquid electrolytes,the interest in solidstate lithium metal batteries is rapidly growing.Among various solid electrolytes,garnet-type lithium lanthanum zirconate (LLZO) has attracted extensive attention due to its numerous advantages.This review systematically summarizes the intrinsic issues faced by unstable bare LLZO and the resolution strategy of metallic doping in the electrochemical application.It comprehensively discusses the doping arrangements for high ionic conductivity based on element types and gap filling using second phases/sintering aids for LLZO grains/pellets.Emphasizing diverse doping strategies for bulk LLZO,it relates to simulation and characterization findings along with novel synthesis approaches.By identifying the inherent scientific questionsof LLZO,this review bridges the long-existing gaps between the doping strategy guidelines for suitable crystalline phase and the surge of high Li^(+)conductivity for practical solid-state lithium batteries.展开更多
Photocatalytic hydrogen production based on semiconductor photocatalysts has been considered as one of the most promising strategies to resolve the global energy shortage.Graphitic carbon nitride(g‐C3N4)has been a st...Photocatalytic hydrogen production based on semiconductor photocatalysts has been considered as one of the most promising strategies to resolve the global energy shortage.Graphitic carbon nitride(g‐C3N4)has been a star visible‐light photocatalyst in this field due to its various advantages.However,pristine g‐C3N4usually exhibits limited activity.Herein,to enhance the performance of g‐C3N4,alkali metal ion(Li+,Na+,or K+)‐doped g‐C3N4are prepared via facile high‐temperature treatment.The prepared samples are characterized and analyzed using the technique of XRD,ICP‐AES,SEM,UV‐vis DRS,BET,XPS,PL,TRPL,photoelectrochemical measurements,photocatalytic tests,etc.The resultant doped photocatalysts show enhanced visible‐light photocatalytic activities for hydrogen production,benefiting from the increased specific surface areas(which provide more active sites),decreased band gaps for extended visible‐light absorption,and improved electronic structures for efficient charge transfer.In particular,because of the optimal tuning of both microstructure and electronic structure,the Na‐doped g‐C3N4shows the most effective utilization of photogenerated electrons during the water reduction process.As a result,the highest photocatalytic performance is achieved over the Na‐doped g‐C3N4photocatalyst(18.7?mol/h),3.7times that of pristine g‐C3N4(5.0?mol/h).This work gives a systematic study for the understanding of doping effect of alkali metals in semiconductor photocatalysis.展开更多
To maximize the catalytic performance of MoS_(2) in the hydrogen evolution reaction,we investigate the electrocatalytic and photocatalytic performance of monolayer MoS_(2) doped with noble metal(Ag,Au,Cu,Pd,and Pt)usi...To maximize the catalytic performance of MoS_(2) in the hydrogen evolution reaction,we investigate the electrocatalytic and photocatalytic performance of monolayer MoS_(2) doped with noble metal(Ag,Au,Cu,Pd,and Pt)using first principles calculation combined with the climbing image nudged elastic band method.We find the band gap of the monolayer MoS_(2) is reduced significantly by the noble metal doping,which is unfavorable to improving its photocatalytic performance.The optical absorption coefficient shows that the doping does not increase the ability of the monolayer MoS_(2) to absorb visible light.The monolayer MoS_(2) doped with the noble metal is not a potential photocatalyst for the hydrogen evolution reaction because the band edge position of the conduction band minimum is lower than-4.44 eV,the reduction potential of H^(+)/H_(2).Fortunately,the band gap reduction increases the electron transport performance of the monolayer MoS_(2),and the activation energy of water splitting is greatly reduced by the noble metal doping,especially the Pt doping.On the whole,noble metal doping can enhance the electrocatalytic performance of the monolayer MoS_(2).展开更多
Metal–organic frameworks (MOFs) as photocatalysts and photocatalyst supports combine several advantages of homogeneous and heterogeneous catalyses, including stability, post-reaction separation, catalyst reusability,...Metal–organic frameworks (MOFs) as photocatalysts and photocatalyst supports combine several advantages of homogeneous and heterogeneous catalyses, including stability, post-reaction separation, catalyst reusability,and tunability, and they have been intensively studied for photocatalytic applications. There are several reviews that focus mainly or even entirely on experimental work. The present review is intended to complement those reviews by focusing on computational work that can provide a further understanding of the photocatalytic properties of MOF photocatalysts. We first present a summary of computational methods, including density functional theory, combined quantum mechanical and molecular mechanical methods, and force fields for MOFs. Then, computational investigations on MOF-based photocatalysis are briefly discussed. The discussions focus on the electronic structure, photoexcitation, charge mobility, and photoredox catalysis of MOFs, especially the widely studied Ui O-66-based MOFs.展开更多
Despite of considerable efforts on the MnO2-based catalytic combustion,the different structural and component requirements of MnO2 for gas-phase selective oxidation and complete oxidation largely remain unknown.By com...Despite of considerable efforts on the MnO2-based catalytic combustion,the different structural and component requirements of MnO2 for gas-phase selective oxidation and complete oxidation largely remain unknown.By comparing four types of MnO2 with different crystal structures(α,β,γandδ),γ-MnO2 was found to be the most efficient catalyst for both aerobic selective oxidation of ethanol and CO oxidation.The structural effect ofγ-MnO2 was further investigated by doping metal ions into the framework and by comparing the catalytic performance in the gas-phase aerobic oxidation of CO and ethanol.Among ten M-γ-MnO2 catalysts,Zn-γ-MnO2 showed the lowest temperature(160°C)for achieving 90%CO conversion.The CO oxidation activity of the M-γ-MnO2 catalysts was found to be more relevant to the surface acidity-basicity than the reducibility.In contrast,surface reducibility has been demonstrated to be more crucial in the gas-phase ethanol oxidation.Cu-γ-MnO2 with higher reducibility and more oxygen vacancies of Mn^2+/Mn^3+species exhibited higher catalytic activity in the selective ethanol oxidation.Cu-γ-MnO2 achieved the highest acetaldehyde yield(75%)and space-time-yield(5.4 g gcat^-1 h^-1)at 200°C,which are even comparable to the results obtained by the state-of-the-art silver and gold-containing catalysts.Characterization results and kinetic studies further suggest that the CO oxidation follows the lattice oxygen-based Mars-van Krevelen mechanism,whereas both surface lattice oxygen and adsorbed oxygen species involve in the ethanol activation.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.22033002,21525311,21773027)the Scientific Research Foundation of Graduate School of Southeast University(YBPY1920)+1 种基金the China Postdoctoral Science Foundation(Grant No.2020M681450)the China Scholarship Council(CSC,201906090150)。
文摘Effectively controlling the selectivity of C_(2) oxygenates is desirable for electrocatalytic CO_(2) reduction.Copper catalyst has been considered as the most potential for reducing CO_(2) to C_(2) products,but it still suffers from low C_(2) selectivity,high overpotential,and competitive hydrogen evolution reaction(HER).Here,we propose a design strategy to introduce a second metal that weakly binds to H and a functional ligand that provides hydrogen bonds and protons to achieve high selectivity of C_(2)oxygenates and effective suppression of HER on the Cu(100)surface simultaneously.Seven metals and eleven ligands are screened using first-principles calculations,which shows that Sn is the most efficient for inhibiting HER and cysteamine(CYS)ligand is the most significant in reducing the limiting potential of^(*)CO hydrogenation to^(*)CHO.In the post C-C coupling steps,a so-called“pulling effect”that transfers H in the CYS ligand as a viable proton donor to the C_(2)intermediate to form an H bond,can further stabilize the OH group and facilitate the selection of C_(2)products toward oxygenates.Therefore,this heterogeneous electrocatalyst can effectively reduce CO_(2)to ethanol and ethylene glycol with an ultra-low limiting potential of-0.43 V.This study provides a new strategy for effectively improving the selectivity of C_(2)oxygenates and inhibiting HER to achieve advanced electrocatalytic CO_(2)reduction.
文摘Surface properties （viz. surface area, basicity/base strength distribution, and crystal phases） of alkali metal doped CaO （alkali metal/Ca= 0.1 and 0.4） catalysts and their catalytic activity/selectivity in oxidative coupling of methane （OCM） to higher hydrocarbons at different reaction conditions （viz. temperature, 700 and 750 ℃; CH4/O2 ratio, 4.0 and 8.0 and space velocity, 5140-20550 cm^3 ·g^-1·h^-1） have been investigated. The influence of catalyst calcination temperature on the activity/selectivity has also been investigated. The surface properties （viz. surface area, basicity/base strength distribution） and catalytic activity/selectivity of the alkali metal doped CaO catalysts are strongly influenced by the alkali metal promoter and its concentration in the alkali metal doped CaO catalysts. An addition of alkali metal promoter to CaO results in a large decrease in the surface area but a large increase in the surface basicity （strong basic sites） and the C2＋ selectivity and yield of the catalysts in the OCM process. The activity and selectivity are strongly influenced by the catalyst calcination temperature. No direct relationship between surface basicity and catalytic activity/selectivity has been observed. Among the alkali metal doped CaO catalysts, Na-CaO （Na/Ca = 0.1, before calcination） catalyst （calcined at 750 ℃）, showed best performance （C2＋ selectivity of 68.8% with 24.7% methane conversion）, whereas the poorest performance was shown by the Rb-CaO catalyst in the OCM process.
基金supported by the National Key Laboratory on Electromagnetic Environmental Effects(No.6142205240402)the National Natural Science Foundation of China(No.52103223)+3 种基金the Natural Science Foundation of Heilongjiang Province of China(No.YQ2023E027)the Fundamental Research Funds for the Central Universities(Nos.3072024GH2605,3072024XX2613,and 3072024XX2616)Young Talent of Lifting engineering for Science and Technology in Shandong,China(No.SDAST2025QTB019)for supporting this researchwe thank the Shandong Natural Science Foundation(Nos.ZR2024MA011 and ZR2023QA049)for their support in the theoretical calculation of this work.
文摘W_(18)O_(49)is a promising multifunctional material for electrochromic energy storage applications,owing to its abundant oxygen vacancies and distinctive crystalline structure.However,the contradiction between the high transmittance modulation for electrochromism and the high material loading for energy storage severely restricts the development of W_(18)O_(49)in multifunctional smart windows.This work found that different metal doping(Mo,Ti,Fe)exhibited significant differences in regulating the electrochromic performance and energy storage of W_(18)O_(49).And the oxygen vacancies of W_(18)O_(49)can be further controlled by adjusting the metal doping concentration,simultaneously achieving excellent electrochromic properties and energy storage.5%Ti-doped W_(18)O_(49)not only exhibits a high transmittance modulation of 82.3%(633 nm)and 81.0%(1050 nm)with fast coloration/bleaching times of 9.8/5.8 and 3.8/5.8 s,but also shows a good energy storage of 32.5 mF·cm^(-2)at 0.1 mA·cm^(-2).Theoretical calculations indicate Ti doped W_(18)O_(49)shows a more delocalized characteristic in band decomposition charge densities and a lower diffusion energy barrier,which is conducive to enhancing the electrochemical performance.This work demonstrates metal doping plays a significant role in simultaneously regulating electrochromism and energy storage,providing a new perspective for the development of multifunctional electrochromic materials.
基金supported by the Korea Institute for Advancement of Technology(KIAT)and the Ministry of Trade,Industry and Energy(MOTIE),Republic of Korea(Grant P0017363)by the National Research Foundation of Korea(NRF),Ministry of Science and ICT,South Korea(Grants 2022R1A2C1011559 and RS-2024-00405818)This study is the result of a research project conducted with the funds of the Open R&D program of Korea Electric Power Corporation(R23XO04).
文摘As for the high sustainable solar hydrogen production via water splitting,transition metal doping on an oxide photoanode in photoelectrochemical(PEC)cells has been recognized as an effective approach.However,conventional thermal-diffusionmediated doping strategies face the challenge of resolving sluggish catalytic kinetics for oxygen evolution reaction(OER)and its practical utilization for the synthesis of photoanode films.Herein,we introduce facile ultrafast flame-boosted doping of Mo into a BiVO_(4)(FL MoBVO)film for 20 s to achieve an efficient PEC OER.Mo elements in a low-valence state(i.e.,Mo^(6−δ))and Mo^(6+)are successfully doped into the photoanode,which manipulate the energy band structure,facilitating the downward shift of band edges and promoting the surface catalytic kinetics.Consequently,the flame-boosted Mo-doping results in superior PEC performance in a mild environment with neutral electrolyte without introducing any other additives or co-catalysts,where the photocurrent density at 1.23 V_(RHE) under 1 sun illumination in pH 7 is outstandingly enhanced,over 9-fold higher than that of a pristine BiVO_(4).The flame-boosted doping induces significantly enhanced photoexcited charge transport and catalytic reaction kinetics performances simultaneously.Our report provides the effective strategy boosting both the thermodynamic and kinetic charge migration properties for sustainable materials.
文摘Durable and inexpensive graphitic carbon nitride(g-C_(3)N_(4))demonstrates great potential for achieving efficient photocatalytic hydrogen evolution reduction(HER).To further improve its activity,g-C_(3)N_(4)was subjected to atomic-level structural engineering by doping with transition metals(M=Fe,Co,or Ni),which simultaneously induced the formation of metal-N active sites in the g-C_(3)N_(4)framework and modulated the bandgap of g-C_(3)N_(4).Experiments and density functional theory calculations further verified that the as-formed metal-N bonds in M-doped g-C_(3)N_(4)acted as an"electron transfer bridge",where the migration of photo-generated electrons along the bridge enhanced the efficiency of separation of the photogenerated charges,and the optimized bandgap of g-C_(3)N_(4)afforded stronger reduction ability and wider light absorption.As a result,doping with either Fe,Co,or Ni had a positive effect on the HER activity,where Co-doped g-C_(3)N_(4)exhibited the highest performance.The findings illustrate that this atomic-level structural engineering could efficiently improve the HER activity and inspire the design of powerful photocatalysts.
基金supported by the Science and Technology Major Project of Shanxi Province,China (Grant No. 20181102013)the Fund from the “1331 Project”Engineering Research Center of Shanxi Province,China (Grant No. PT201801)。
文摘Nano-diamond particles are co-deposited on Ti substrates with metal(Ti/Ni) nanoparticles(NPs) by the electrophoretic deposition(EPD) method combined with a furnace annealing at 800℃ under N_(2) atmosphere. Modifications of structural and electron field emission(EFE) properties of the metal-doped films are investigated with different metal NPs concentrations. Our results show that the surface characteristics and EFE performances of the samples are first enhanced and then reduced with metal NPs concentration increasing. Both the Ti-doped and Ni-doped nano-diamond composite films exhibit optimal EFE and microstructural performances when the doping quantity is 5 mg. Remarkably enhanced EFE properties with a low turn-on field of 1.38 V/μm and a high current density of 1.32 mA/cm^(2) at an applied field of 2.94 V/μm are achieved for Ni-doped nano-diamond films, and are superior to those for Ti-doped ones. The enhancement of the EFE properties for the Ti-doped films results from the formation of the TiC-network after annealing. However, the doping of electron-rich Ni NPs and formation of high conductive graphitic phase are considered to be the factor, which results in marvelous EFE properties for these Ni-doped nano-diamond films.
基金Project supported by the National Natural Science Foundation of China(22102141)。
文摘The utilization of visible light for photocatalytic nitrogen fixation offers a sustainable and eco-friendly strategy for the production of ammonia.The present study focuses on the synthesis of a series of rare earth-doped carbon nitride composite ultraviolet-activated Ce-UiO-66 catalysts,denoted as RECNactMOF,for efficient nitrogen fixation.Rare earth doping modulates the band structure of carbon nitride,facilitating the formation of a type-I heterojunction with Ce-UiO-66 and promoting photocarrier generation at nitrogen fixation sites.Among these,Sm-doped SmCN-actMOF exhibits high visible-light absorption and efficient utilization of photocarriers,resulting in an apparent quantum efficiency(AQE)of 1.58%under 495 nm light irradiation.This study provides a pathway for enhancing the nitrogen fixation efficiency of photocatalysts through the incorporation of rare earth elements,and expanding the potential applications of rare earth materials in the field of photocatalysis.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(NRF-2022R1A2C1011559,No.RS-2024-00405818 and NRF-2021M3H4A6A01045764)by the National Supercomputing Center with supercomputing resources including technical support(KSC-2024-CRE-0196)by Korea Basic Science Institute(National Research Facilities and Equipment Center)grant funded by the Ministry of Science and ICT(No.RS-2024-00404712).
文摘Hydrogen evolution reaction(HER)in acidic media has been spotlighted for hydrogen production since it is a favourable kinetics with the supplied protons from a counterpart compared to that within alkaline environment.However,there is no choice but to use a platinum-based catalyst yet.As for a noble metal-free electrocatalyst,incorporation of earth-abundant transition metal(TM)atoms into nanocarbon platforms has been extensively adopted.Although a data-driven methodology facilitates the rational design of TM-anchored carbon catalysts,its practical application suffers from either a simplified theoretical model or the prohibitive cost and complexity of experimental data generation.Herein,an effective and facile catalyst design strategy is proposed based on machine learning(ML)and its model verification using electrochemical methods accompanied by density functional theory simulations.Based on a Bayesian genetic algorithm ML model,the Ni-incorporated carbon quantum dots(Ni@CQD)loaded on a three-dimensional reduced graphene oxide conductor are proposed as the best HER catalyst amongst the various TM-incorporated CQDs under the optimal conditions of catalyst loading,electrode type,and temperature and pH of electrolyte.The ML results are validated with electrochemical experiments,where the Ni@CQD catalyst exhibited superior HER activity,requiring an overpotential of 151 mV to achieve 10 mAcm^(−2) with a Tafel slope of 52 mV dec^(−1) and impressive durability in acidic media up to 100 h.This methodology can provide an effective route for the rational design of highly active electrocatalysts for commercial applications.
基金financially supported by the Natural Science Foundation of Jiangsu Province(BK20240972)the Changzhou Leading Innovative Talents Introduction and Cultivation Project(Nos.CQ20230109 and CQ20230108)+1 种基金the Jiangsu Provincial Double-Innovation Doctor(No.JSSCBS20230439)the National Natural Science Foundation of China Key Program(No.U22A20420).
文摘Due to its high electrical conductivity and platinum-like electronic structure,molybdenum phosphide(MoP)has attracted extensive attention as a potential catalyst for the hydrogen evolution reaction(HER)by water splitting.Nevertheless,in the oxygen evolution reaction(OER),the electrocatalytic performance of MoP did not achieve satisfactory results.Therefore,novel nitrogen-doped carbon-encapsulated Ladoped MoP nanoparticles(La-MoP@N/C)are synthesized,which show outstanding durability and electrocatalytic activity in both HER and OER.Detailed structural characterization and calculations confirm that La doping not only effectively adjusts the electron density around Mo and P atoms,accelerates the adsorption and desorption processes,but also increases the number of active sites.Low overpotentials of 113 and 388 mV for HER and OER at 10 mA cm−2 are achieved with the optimized La0.025-Mo0.975P@N/C.Furthermore,the two-electrode electrolyzer assembled with La0.025-Mo0.975P@N/C also presents impressive water splitting performance.This study indicates that rare earth doping can be used as an efficient strategy to control the local electronic structure of phosphides precisely,which can also be extended to other electrocatalysts.
基金supported by the National Key Research and Development Program of China(No.2022YFB3505301)the National Key Research and Development Program of Shanxi Province(No.202302050201014)+2 种基金the National Natural Science Foundation of China(No.12304148)the Natural Science Basic Research Program of Shanxi Province(No.202203021222219)the China Postdoctoral Science Foundation(No.2023M731452).
文摘Alloying with transition metal elements akin to Sm(CoFeCuZr)z can effectively enhance the magnetic properties of SmCo-based permanent magnets.However,the effects of transition metals doping on its magnetic properties,detailed atomic occupancy and the mechanism for structural stability remain unclear.Specifically,for SmCo3 magnets,there is minimal theoretical study available.Herein,based on first-principles calculations,we systematically investigated the influence of 3d transition metals(TMs)doping on the structural stability,magnetic properties and electronic characteristics of SmCo3 magnets.Our results show that Sc,Ti,V,Fe,Ni,Cu and Zn preferentially occupy the 18h lattice site,while Cr and Mn occupy the 3b and 6c lattice sites,respectively.Doping with Ti,Cr,Mn,Fe,Ni,Cu and Zn contributes to enhancing the stability of SmCo3,whereas the doping of Sc and V adversely affects structural stability.The magnetic calculations reveal that Cr,Mn and Fe doping significantly enhances the total magnetic moment.It is also found that lower concentrations of Cr doping can significantly enhance the magnetocrystalline anisotropy energy(MAE).More intriguingly,when the doping concentrations of Sc,Ni and Cu reach 14.81 at%,22.22 at%and 22.22 at%,respectively,the magnetic easy axis of the system shifts from out-of-plane to in-plane.The optimal doping concentration of Fe in the SmCo_(3) system is determined to be 37.04 at%.The Curie temperature of pure SmCo_(3) is 483.9 K.Our theoretical study offers valuable theoretical guidance for experimental exploration toward SmCo-based permanent magnets with higher performance.
基金financially supported by the National Key R&D Program of China(Nos.2021YFC1910504 and 2024YFC3907701)the National Energy-Saving and Low-Carbon Materials Production and Application Demonstration Platform Program(No.TC220H06N)+2 种基金the Fundamental Research Funds for the Central Universities(No.FRF-EYIT-23-07)the National Natural Science Foundation of China(No.52204412)Beijing Natural Science Foundation(No.2242046)
文摘Transition metal-doped CeO_(2)catalysts exhibit great potentials for the selective catalytic reduction(SCR)of nitrogen oxide(NOx)with NH_(3)(NH_(3)-SCR).However,traditional research mainly relies on a lot of experiments to find out effective catalysts,which wastes a lot of time and resources.Screening out effective CeO_(2)-based catalysts for low-temperature NH_(3)-SCR via density functional theory(DFT)calculations is crucial for the rational design and synthesis of efficient catalysts.Herein,transition metal(M=Co,Cr,Cu,Fe,Mn,Mo,Nb,Ni,Ta,Ti,V,and W)-doped CeO_(2)catalysts were screened out via accelerated DFT calculations for NH_(3)-SCR of nitric-oxide(NO)using three theoretical terms;(i)an adsorption energy of NH_(3),(ii)an adsorption energy of NO,and(iii)the reaction energies between NO with O_(2)and lattice oxygen.The theoretically predicted trend in catalytic performance is as follows:CeO_(2)-Mn,-Cu,-Mo>CeO_(2)-Fe,-Co,-Ni,-V,-Cr>CeO_(2)-W,-Ti>CeO_(2)-Nb,-Ta.The theoretical prediction was well verified via experimental NH_(3)-SCR activity of NO at low temperatures(90–300℃),demonstrating CeO_(2)-Mo as efficient NH_(3)-SCR catalyst across a broad temperature range.Temperature-programmed desorption of NH_(3)and in situ diffuse reflectance infrared Fourier transforms spectroscopy further indicated that metal doping significantly enhanced the NH_(3)adsorption capacity and strength of CeO_(2)in the medium-to low-temperature range.Consequently,accelerated DFT calculations provide a useful tool with great potentials for predicting the catalytic performance.
文摘Metal-organic frameworks （MOFs） have attracted much attention as adsorbents for the separation of CO2 from flue gas or natural gas. Here, a typical metal-organic framework HKUST-I（also named Cu-BTC or MOF-199） was chemically reduced by doping it with alkali metals （Li, Na and K） and they were further used to investigate their CO2 adsorption capacities. The structural information, surface chemistry and thermal behavior of the prepared adsorbent samples were characterized by X-ray powder diffraction （XRD）, thermo-gravimetric analysis （TGA） and nitrogen adsorption-desorption isotherm analysis. The results showed that the CO2 storage capacity of HKUST-1 doped with moderate quantities of Li＋, Na＋ and K＋, individually, was greater than that of unmodified HKUST-1. The highest CO2 adsorption uptake of 8.64 mmol/g was obtained with 1K-HKUST-1, and it was ca. 11% increase in adsorption capacity at 298 K and 18 bar as compared with HKUST- 1. Moreover, adsorption tests showed that HKUST-1 and 1K-HKUST-1 displayed much higher adsorption capacities of CO2 than those of N2. Finally, the adsorption/desorption cycle experiment revealed that the adsorption performance of 1K-HKUST-1 was fairly stable, without obvious deterioration in the adsorption capacity of CO2 after 10 cycles.
基金Project supported by the National Key Research and Development Program of China(2016YFC0204300)the National Natural Science Foundation of China(21477109)。
文摘A series of transition metals(Fe,Co,Ni,Cu,Cr and Mn)-doped CeO_(2)-TiO_(2) catalysts were prepared by the sol-gel method and applied for the catalytic removal of 1,2-dichloroethane(DCE) as a model for chlorinated VOCs(CVOCs).The various characterization methods including X-ray diffraction(XRD),N_(2) adsorption-desorption,UV-Raman,NH_(3) temperature-programmed desorption(NH_(3)-TPD) and H_(2) temperature-programmed reduction(H_(2)-TPR) were utilized to investigate the physicochemical properties of the catalysts.The results show that doping Fe,Co,Ni or Mn can obviously promote the activity of CeO_(2)-TiO_(2) mixed oxides for DCE degradation,which is related to their improved texture properties,acid sites(especially for strong acidity) and low-temperature reducibility.Particularly,CeTi-Fe doped with moderate Fe exhibits excellent activity for 1,2-dichloroethane(DCE) degradation,giving a T_(90%) value as low as 250℃.More importantly,only trace chlorinated byproducts were produced during the low-temperature degradation of various CVOCs(dichloromethane(DCM),trichloroethylene(TCE) and chlorobenzene(CB)) over CeTi-Fe1/9 catalyst with high durability.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2017YFA0303003 and 2016YFA0300300)the National Natural Science Foundation of China(Grant Nos.11834016 and 11888101)+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(Grant Nos.XDB33010200 and XDB25000000)the Strategic Priority Research Program and Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(Grant Nos.QYZDY-SSW-SLH001 and QYZDY-SSW-SLH008)。
文摘The doping effects of transition metals(TMs = Mn, Co, Ni, and Cu) on the superconducting critical parameters are investigated in the films of iron selenide(Li,Fe)OHFe Se. The samples are grown via a matrix-assisted hydrothermal epitaxy method. Among the TMs, the elements of Mn and Co adjacent to Fe are observed to be incorporated into the crystal lattice more easily. It is suggested that the doped TMs mainly occupy the iron sites of the intercalated(Li,Fe)OH layers rather than those of the superconducting Fe Se layers. We find that the critical current density J_(c) can be enhanced much more strongly by the Mn dopant than the other TMs, while the critical temperature T_(c) is weakly affected by the TM doping.
基金Project supported by the National Natural Science Foundation of China (Grant No. 11664023)the Hong Liu First-class Disciplines Development Program of Lanzhou University of TechnologyState Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals of China
文摘The influence of transition metals(Sc,Ti,V,Cr,and Mn)doping at different distances on the magnetism of CdS is studied by using generalized gradient approximation combined with Hubbard U in the VASP package.The results show that the doping systems are more stable,easy to form,and the wurtzite structure of CdS is not changed.It is found that the systems are antiferromagnetic(AFM)when nearest neighbor doping,which is attributed to the direct charge transfers between two impurity ions.The systems are ferromagnetic(FM)when the doping distance increases further,since the double exchange interactions are observed among the 3d orbital of the transition metal,the Cd-5s and the S-3p orbitals are at conduction band minimum.We also found that the total magnetic moment of each ferromagnetic system increases with the order of SC to Mn-doping,the spin polarizability of Cr-doping system is 100%.The estimated Curie temperature indicates that the Cr-and Mn-doped CdS in this paper can achieve room-temperature ferromagnetic characteristics,especially the Cr doping is the most prominent.And TM-doping does not destroy the semiconductor characteristics of the system.Therefore,the TM-doped CdS can be used as an ideal dilute magnetic semiconductor functional material.
基金supported by the National Natural Science Foundation of China(No.52303245)the Innovative Training/Entrepreneurial Program for Undergraduate(No.202410057057)the"Huacai"training special program of Tianjin University of Science and Technology
文摘Given the safety concerns and low energy density induced by liquid electrolytes,the interest in solidstate lithium metal batteries is rapidly growing.Among various solid electrolytes,garnet-type lithium lanthanum zirconate (LLZO) has attracted extensive attention due to its numerous advantages.This review systematically summarizes the intrinsic issues faced by unstable bare LLZO and the resolution strategy of metallic doping in the electrochemical application.It comprehensively discusses the doping arrangements for high ionic conductivity based on element types and gap filling using second phases/sintering aids for LLZO grains/pellets.Emphasizing diverse doping strategies for bulk LLZO,it relates to simulation and characterization findings along with novel synthesis approaches.By identifying the inherent scientific questionsof LLZO,this review bridges the long-existing gaps between the doping strategy guidelines for suitable crystalline phase and the surge of high Li^(+)conductivity for practical solid-state lithium batteries.
基金supported by the National Natural Science Foundation of of China(51472191,21407115,21773179)the Natural Science Foundation of Hubei Province of China(2017CFA031)the Opening Project of Key Laboratory of Optoelectronic Chemical Materials and Devices,Ministry of Education(JDGD-201509)~~
文摘Photocatalytic hydrogen production based on semiconductor photocatalysts has been considered as one of the most promising strategies to resolve the global energy shortage.Graphitic carbon nitride(g‐C3N4)has been a star visible‐light photocatalyst in this field due to its various advantages.However,pristine g‐C3N4usually exhibits limited activity.Herein,to enhance the performance of g‐C3N4,alkali metal ion(Li+,Na+,or K+)‐doped g‐C3N4are prepared via facile high‐temperature treatment.The prepared samples are characterized and analyzed using the technique of XRD,ICP‐AES,SEM,UV‐vis DRS,BET,XPS,PL,TRPL,photoelectrochemical measurements,photocatalytic tests,etc.The resultant doped photocatalysts show enhanced visible‐light photocatalytic activities for hydrogen production,benefiting from the increased specific surface areas(which provide more active sites),decreased band gaps for extended visible‐light absorption,and improved electronic structures for efficient charge transfer.In particular,because of the optimal tuning of both microstructure and electronic structure,the Na‐doped g‐C3N4shows the most effective utilization of photogenerated electrons during the water reduction process.As a result,the highest photocatalytic performance is achieved over the Na‐doped g‐C3N4photocatalyst(18.7?mol/h),3.7times that of pristine g‐C3N4(5.0?mol/h).This work gives a systematic study for the understanding of doping effect of alkali metals in semiconductor photocatalysis.
基金the Joint Funds of the National Natural Science Foundation of China(Grant No.U1967212)the National Science and Technology Major Project of China(Grant No.2019XS06004009)the Fundamental Research Funds for the Central Universities(Grant No.2018ZD10).
文摘To maximize the catalytic performance of MoS_(2) in the hydrogen evolution reaction,we investigate the electrocatalytic and photocatalytic performance of monolayer MoS_(2) doped with noble metal(Ag,Au,Cu,Pd,and Pt)using first principles calculation combined with the climbing image nudged elastic band method.We find the band gap of the monolayer MoS_(2) is reduced significantly by the noble metal doping,which is unfavorable to improving its photocatalytic performance.The optical absorption coefficient shows that the doping does not increase the ability of the monolayer MoS_(2) to absorb visible light.The monolayer MoS_(2) doped with the noble metal is not a potential photocatalyst for the hydrogen evolution reaction because the band edge position of the conduction band minimum is lower than-4.44 eV,the reduction potential of H^(+)/H_(2).Fortunately,the band gap reduction increases the electron transport performance of the monolayer MoS_(2),and the activation energy of water splitting is greatly reduced by the noble metal doping,especially the Pt doping.On the whole,noble metal doping can enhance the electrocatalytic performance of the monolayer MoS_(2).
基金supported as part of the Nanoporous Materials Genome Center by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences, under Award No. DE-FG0217ER16362
文摘Metal–organic frameworks (MOFs) as photocatalysts and photocatalyst supports combine several advantages of homogeneous and heterogeneous catalyses, including stability, post-reaction separation, catalyst reusability,and tunability, and they have been intensively studied for photocatalytic applications. There are several reviews that focus mainly or even entirely on experimental work. The present review is intended to complement those reviews by focusing on computational work that can provide a further understanding of the photocatalytic properties of MOF photocatalysts. We first present a summary of computational methods, including density functional theory, combined quantum mechanical and molecular mechanical methods, and force fields for MOFs. Then, computational investigations on MOF-based photocatalysis are briefly discussed. The discussions focus on the electronic structure, photoexcitation, charge mobility, and photoredox catalysis of MOFs, especially the widely studied Ui O-66-based MOFs.
文摘Despite of considerable efforts on the MnO2-based catalytic combustion,the different structural and component requirements of MnO2 for gas-phase selective oxidation and complete oxidation largely remain unknown.By comparing four types of MnO2 with different crystal structures(α,β,γandδ),γ-MnO2 was found to be the most efficient catalyst for both aerobic selective oxidation of ethanol and CO oxidation.The structural effect ofγ-MnO2 was further investigated by doping metal ions into the framework and by comparing the catalytic performance in the gas-phase aerobic oxidation of CO and ethanol.Among ten M-γ-MnO2 catalysts,Zn-γ-MnO2 showed the lowest temperature(160°C)for achieving 90%CO conversion.The CO oxidation activity of the M-γ-MnO2 catalysts was found to be more relevant to the surface acidity-basicity than the reducibility.In contrast,surface reducibility has been demonstrated to be more crucial in the gas-phase ethanol oxidation.Cu-γ-MnO2 with higher reducibility and more oxygen vacancies of Mn^2+/Mn^3+species exhibited higher catalytic activity in the selective ethanol oxidation.Cu-γ-MnO2 achieved the highest acetaldehyde yield(75%)and space-time-yield(5.4 g gcat^-1 h^-1)at 200°C,which are even comparable to the results obtained by the state-of-the-art silver and gold-containing catalysts.Characterization results and kinetic studies further suggest that the CO oxidation follows the lattice oxygen-based Mars-van Krevelen mechanism,whereas both surface lattice oxygen and adsorbed oxygen species involve in the ethanol activation.
