The photoreduction of CO_(2)to achieve high-value-added hydrocarbons under simulated sunlight irradiation is advantageous,but challenging.In this study,a series of MgO and Au nanoparticle-co-modified g-C_(3)N_(4)photo...The photoreduction of CO_(2)to achieve high-value-added hydrocarbons under simulated sunlight irradiation is advantageous,but challenging.In this study,a series of MgO and Au nanoparticle-co-modified g-C_(3)N_(4)photocatalysts were synthesized and subsequently applied for the photocatalytic reduction of CO_(2)with H2O under simulated solar irradiation.The best photocatalytic performance was demonstrated by the Au and 3%MgO-co-modified g-C_(3)N_(4)photocatalysts with CO,CH_(4),CH3OH,and CH3CHO yields of 423.9,83.2,47.2,and 130.4μmol/g,respectively,in a 3-h reaction.We investigated the effects of MgO and Au as cocatalysts on photocatalytic behaviors,respectively.The characterizations and experimental results showed that the enhanced photocatalytic activity was due to the synergistic effect among the components of the ternary photocatalyst.The cocatalyst MgO can activate CO_(2)(adsorbed at the interface between the MgO and Au particles),and the Mg-N bonds formed in the MgO-CN nanosheets played an important role in the charge transfer.Meanwhile,the Au particles that were modified into MgO/g-C_(3)N_(4)can increase the absorption of visible light via the surface plasmon resonance effect and further reduce the activation energies of the photoreduction of CO_(2)using H2O.This study provided an effective method for the modification of traditional primary photocatalysts with promising performance for photocatalytic CO_(2)reduction.展开更多
Nowadays catalytic nitrogen reduction reaction(NRR)by electrochemistry has attracted much attention because of its key role in producing the basic chemical product ammonia with low energy consumption.A stable and envi...Nowadays catalytic nitrogen reduction reaction(NRR)by electrochemistry has attracted much attention because of its key role in producing the basic chemical product ammonia with low energy consumption.A stable and environmentally‐friendly single‐or multi‐atom catalyst with good performance in activity and selectivity is highly desired for NRR.From density functional theory calculations,the NRR mechanisms catalyzed by Nb monomer,dimer,trimer and tetramer anchored on graphitic carbon nitride(Nb_(x)@g‐C_(3)N_(4),x=1,2,3,4)have been deeply explored.It has been found that Nb_(3)@g‐C_(3)N_(4) exhibits the best catalytic ability among the four catalysts with the introduction of H+.A more stable intermediate(*NH_(2)+*H)can be found to reduce the huge free energy barrier of forming*NH_(3) from*NH_(2) directly in a multi‐atom system.By analyzing the density of states and projected crystal orbital Hamilton population,a synergistic effect among Nb atoms and the adsorbed H^(+)is responsible for reducing the overpotential of NRR.Furthermore,the competitive hydrogen evolution reaction is suppressed effectively.This work introduces a new insight in the reaction pathway in multi‐atoms for developing high‐efficiency NRR catalysts.展开更多
Regulating charge transfer to achieve specific transfer path can improve electron utilization and complete efficient photoreduction of CO_(2).Here,we fabricated a S-scheme heterojunction of CN/Fe-MOF by an in-situ ass...Regulating charge transfer to achieve specific transfer path can improve electron utilization and complete efficient photoreduction of CO_(2).Here,we fabricated a S-scheme heterojunction of CN/Fe-MOF by an in-situ assembly strategy.The S-scheme charge transfer mechanism was confirmed by band structure,electron spin resonance(ESR)and work function(Φ)analysis.On the one hand,the response of Fe-MOF in the visible region improved the utilization of light energy,thus increasing the ability of CN/Fe-MOF to generate charge carriers.On the other hand,CN,as the active site,not only had strong adsorption capacity for CO_(2),but also retained photogenerated electrons with high reduction capacity because of S-scheme charge transfer mechanism.Hence,in the absence of any sacrificial agent and cocatalyst,the optimized 50CN/Fe-MOF obtained the highest CO yield(19.17μmol g^(–1))under UV-Vis irradiation,which was almost 10 times higher than that of CN.In situ Fourier transform infrared spectra not only revealed that the photoreduction of CO_(2) occurred at the CN,but also demonstrated that the S-scheme charge transfer mechanism enabled 50CN/Fe-MOF to have a stronger ability to generate HCOO–than CN.展开更多
基金supported by the National Natural Science Foundation(51772283,22072140)the Fundamental Research Funds for the Central Universities(WK2060000032)the Hong Kong Scholars Program(XJ2019022)。
文摘The photoreduction of CO_(2)to achieve high-value-added hydrocarbons under simulated sunlight irradiation is advantageous,but challenging.In this study,a series of MgO and Au nanoparticle-co-modified g-C_(3)N_(4)photocatalysts were synthesized and subsequently applied for the photocatalytic reduction of CO_(2)with H2O under simulated solar irradiation.The best photocatalytic performance was demonstrated by the Au and 3%MgO-co-modified g-C_(3)N_(4)photocatalysts with CO,CH_(4),CH3OH,and CH3CHO yields of 423.9,83.2,47.2,and 130.4μmol/g,respectively,in a 3-h reaction.We investigated the effects of MgO and Au as cocatalysts on photocatalytic behaviors,respectively.The characterizations and experimental results showed that the enhanced photocatalytic activity was due to the synergistic effect among the components of the ternary photocatalyst.The cocatalyst MgO can activate CO_(2)(adsorbed at the interface between the MgO and Au particles),and the Mg-N bonds formed in the MgO-CN nanosheets played an important role in the charge transfer.Meanwhile,the Au particles that were modified into MgO/g-C_(3)N_(4)can increase the absorption of visible light via the surface plasmon resonance effect and further reduce the activation energies of the photoreduction of CO_(2)using H2O.This study provided an effective method for the modification of traditional primary photocatalysts with promising performance for photocatalytic CO_(2)reduction.
文摘Nowadays catalytic nitrogen reduction reaction(NRR)by electrochemistry has attracted much attention because of its key role in producing the basic chemical product ammonia with low energy consumption.A stable and environmentally‐friendly single‐or multi‐atom catalyst with good performance in activity and selectivity is highly desired for NRR.From density functional theory calculations,the NRR mechanisms catalyzed by Nb monomer,dimer,trimer and tetramer anchored on graphitic carbon nitride(Nb_(x)@g‐C_(3)N_(4),x=1,2,3,4)have been deeply explored.It has been found that Nb_(3)@g‐C_(3)N_(4) exhibits the best catalytic ability among the four catalysts with the introduction of H+.A more stable intermediate(*NH_(2)+*H)can be found to reduce the huge free energy barrier of forming*NH_(3) from*NH_(2) directly in a multi‐atom system.By analyzing the density of states and projected crystal orbital Hamilton population,a synergistic effect among Nb atoms and the adsorbed H^(+)is responsible for reducing the overpotential of NRR.Furthermore,the competitive hydrogen evolution reaction is suppressed effectively.This work introduces a new insight in the reaction pathway in multi‐atoms for developing high‐efficiency NRR catalysts.
文摘Regulating charge transfer to achieve specific transfer path can improve electron utilization and complete efficient photoreduction of CO_(2).Here,we fabricated a S-scheme heterojunction of CN/Fe-MOF by an in-situ assembly strategy.The S-scheme charge transfer mechanism was confirmed by band structure,electron spin resonance(ESR)and work function(Φ)analysis.On the one hand,the response of Fe-MOF in the visible region improved the utilization of light energy,thus increasing the ability of CN/Fe-MOF to generate charge carriers.On the other hand,CN,as the active site,not only had strong adsorption capacity for CO_(2),but also retained photogenerated electrons with high reduction capacity because of S-scheme charge transfer mechanism.Hence,in the absence of any sacrificial agent and cocatalyst,the optimized 50CN/Fe-MOF obtained the highest CO yield(19.17μmol g^(–1))under UV-Vis irradiation,which was almost 10 times higher than that of CN.In situ Fourier transform infrared spectra not only revealed that the photoreduction of CO_(2) occurred at the CN,but also demonstrated that the S-scheme charge transfer mechanism enabled 50CN/Fe-MOF to have a stronger ability to generate HCOO–than CN.
