Photocatalytic solar fuel generation is currently a hot topic because of its potential for solving the energy crisis owing to its low cost and zero-carbon emissions.However,the rapid bulk recombination of photoexcited...Photocatalytic solar fuel generation is currently a hot topic because of its potential for solving the energy crisis owing to its low cost and zero-carbon emissions.However,the rapid bulk recombination of photoexcited carrier pairs is a fundamental disadvantage.To resolve this problem,we synthesized a dual cocatalysts system of cobalt phosphide(Co P)and molybdenum carbide(Mo_(2)C)embedded on strontium titanate(Sr TiO_(3))nanofibers.Compared with those of pristine SrTiO_(3) and binary samples,the dual cocatalysts system(denoted SCM)showed a significant improvement in the hydrogen evolution and CO_(2) reduction performance.Further,the structure of SCM effectively promoted spatial charge separation and enhanced the photocatalytic performance.In addition,the Schottky junction formed between the SrTiO_(3) and cocatalysts enabled the rapid transfer of photoexcited electrons from SrTiO_(3) to the cocatalysts,resulting in effective separation and prolonged photoexcited electron lifetimes.The electron migration route between SrTiO_(3) and the cocatalysts was determined by in situ irradiation X-ray spectroscopy,and band structures of Sr TiO_(3) and the cocatalysts are proposed based on results obtained from UV-vis diffraction reflection spectroscopy and ultraviolet photoelectron spectroscopy measurements.On the basis of our results,the dual cocatalysts unambiguously boosts charge separation and enhances photocatalytic performance.In summary,we have investigated the flux of photoexcited electrons in a dual cocatalysts system and provided a theoretical basis and ideas for subsequent research.展开更多
Constructing step-scheme(S-scheme)heterojunctions has been confirmed as a promising strategy for enhancing the photocatalytic activity of composite materials.In this work,a series of sulfur-doped g-C3N4(SCN)/TiO2 S-sc...Constructing step-scheme(S-scheme)heterojunctions has been confirmed as a promising strategy for enhancing the photocatalytic activity of composite materials.In this work,a series of sulfur-doped g-C3N4(SCN)/TiO2 S-scheme photocatalysts were synthesized using electrospinning and calcination methods.The as-prepared SCN/TiO2 composites showed superior photocatalytic performance than pure TiO2 and SCN in the photocatalytic degradation of Congo Red(CR)aqueous solution.The significant enhancement in photocatalytic activity benefited not only from the 1D well-distributed nanostructure,but also from the S-scheme heterojunction.Furthermore,the XPS analyses and DFT calculations demonstrated that electrons were transferred from SCN to TiO2 across the interface of the SCN/TiO2 composites.The built-in electric field,band edge bending,and Coulomb interaction synergistically facilitated the recombination of relatively useless electrons and holes in hybrid when the interface was irradiated by simulated solar light.Therefore,the remaining electrons and holes with higher reducibility and oxidizability endowed the composite with supreme redox ability.These results were adequately verified by radical trapping experiments,ESR tests,and in situ XPS analyses,suggesting that the electron immigration in the photocatalyst followed the S-scheme heterojunction mechanism.This work can enrich our knowledge of the design and fabrication of novel S-scheme heterojunction photocatalysts and provide a promising strategy for solving environmental pollution in the future.展开更多
Exploiting efficient and low-cost cocatalyst with a facile grafting strategy is of critical importance for significantly boosting the photocatalytic H2-evolution activity.In this study,S2^--adsorbed MoSx nanoparticle ...Exploiting efficient and low-cost cocatalyst with a facile grafting strategy is of critical importance for significantly boosting the photocatalytic H2-evolution activity.In this study,S2^--adsorbed MoSx nanoparticle as a superior H2-evolutoin cocatalyst was successfully grafted on the TiO2 surface to greatly boost its photocatalytic activity via one-step lactic acid-induced synthesis strategy.Herein,the lactic acid can induce the homogeneous production of amorphous MoSx(a-MoSx)nanoparticles from MoS42-precursor,while the symbiotic S2^-ions can be easily and availably self-adsorbed on the a-Mo Sxsurface,resulting in the formation of S2^--adsorbed a-Mo Sxnanoparticles with a small size of 0.5-3 nm.Photocatalytic results manifested that the S2^--adsorbed Mo Sxnanoparticles could dramatically facilitate the H2-generation rate of TiO2 photocatalysts(3452μmol h^-1 g^-1,AQE=16.5%).In situ irradiated XPS in conjunction with transient-state PL and photoelectrochemical tests reveal that the improved H_(2)-generation activity can be ascribed to the synergistic effect of boosted interfacial charge transfer from TiO_(2) to S^(2-)adsorbed Mo Sx and the superior H_(2)-evolution reaction on self-adsorbed S_(2-)ions.In addition,the S^(2-)-adsorbed Mo Sx nanoparticles can also act as the general H_(2)-generation cocatalyst to obviously promote the activity of other typical host photocatalysts such as g-C_(3) N_(4) and Cd S.This work provides an innovative approach to develop high-efficiency Mo Sx-based cocatalyst with boosted interfacial charge transfer toward highly efficient photocatalytic materials.展开更多
文摘Photocatalytic solar fuel generation is currently a hot topic because of its potential for solving the energy crisis owing to its low cost and zero-carbon emissions.However,the rapid bulk recombination of photoexcited carrier pairs is a fundamental disadvantage.To resolve this problem,we synthesized a dual cocatalysts system of cobalt phosphide(Co P)and molybdenum carbide(Mo_(2)C)embedded on strontium titanate(Sr TiO_(3))nanofibers.Compared with those of pristine SrTiO_(3) and binary samples,the dual cocatalysts system(denoted SCM)showed a significant improvement in the hydrogen evolution and CO_(2) reduction performance.Further,the structure of SCM effectively promoted spatial charge separation and enhanced the photocatalytic performance.In addition,the Schottky junction formed between the SrTiO_(3) and cocatalysts enabled the rapid transfer of photoexcited electrons from SrTiO_(3) to the cocatalysts,resulting in effective separation and prolonged photoexcited electron lifetimes.The electron migration route between SrTiO_(3) and the cocatalysts was determined by in situ irradiation X-ray spectroscopy,and band structures of Sr TiO_(3) and the cocatalysts are proposed based on results obtained from UV-vis diffraction reflection spectroscopy and ultraviolet photoelectron spectroscopy measurements.On the basis of our results,the dual cocatalysts unambiguously boosts charge separation and enhances photocatalytic performance.In summary,we have investigated the flux of photoexcited electrons in a dual cocatalysts system and provided a theoretical basis and ideas for subsequent research.
文摘Constructing step-scheme(S-scheme)heterojunctions has been confirmed as a promising strategy for enhancing the photocatalytic activity of composite materials.In this work,a series of sulfur-doped g-C3N4(SCN)/TiO2 S-scheme photocatalysts were synthesized using electrospinning and calcination methods.The as-prepared SCN/TiO2 composites showed superior photocatalytic performance than pure TiO2 and SCN in the photocatalytic degradation of Congo Red(CR)aqueous solution.The significant enhancement in photocatalytic activity benefited not only from the 1D well-distributed nanostructure,but also from the S-scheme heterojunction.Furthermore,the XPS analyses and DFT calculations demonstrated that electrons were transferred from SCN to TiO2 across the interface of the SCN/TiO2 composites.The built-in electric field,band edge bending,and Coulomb interaction synergistically facilitated the recombination of relatively useless electrons and holes in hybrid when the interface was irradiated by simulated solar light.Therefore,the remaining electrons and holes with higher reducibility and oxidizability endowed the composite with supreme redox ability.These results were adequately verified by radical trapping experiments,ESR tests,and in situ XPS analyses,suggesting that the electron immigration in the photocatalyst followed the S-scheme heterojunction mechanism.This work can enrich our knowledge of the design and fabrication of novel S-scheme heterojunction photocatalysts and provide a promising strategy for solving environmental pollution in the future.
基金financially supported by the National Natural Science Foundation of China(Nos.51872221 and 21771142)the Fundamental Research Funds for the Central Universities(No.WUT 2019IB002)。
文摘Exploiting efficient and low-cost cocatalyst with a facile grafting strategy is of critical importance for significantly boosting the photocatalytic H2-evolution activity.In this study,S2^--adsorbed MoSx nanoparticle as a superior H2-evolutoin cocatalyst was successfully grafted on the TiO2 surface to greatly boost its photocatalytic activity via one-step lactic acid-induced synthesis strategy.Herein,the lactic acid can induce the homogeneous production of amorphous MoSx(a-MoSx)nanoparticles from MoS42-precursor,while the symbiotic S2^-ions can be easily and availably self-adsorbed on the a-Mo Sxsurface,resulting in the formation of S2^--adsorbed a-Mo Sxnanoparticles with a small size of 0.5-3 nm.Photocatalytic results manifested that the S2^--adsorbed Mo Sxnanoparticles could dramatically facilitate the H2-generation rate of TiO2 photocatalysts(3452μmol h^-1 g^-1,AQE=16.5%).In situ irradiated XPS in conjunction with transient-state PL and photoelectrochemical tests reveal that the improved H_(2)-generation activity can be ascribed to the synergistic effect of boosted interfacial charge transfer from TiO_(2) to S^(2-)adsorbed Mo Sx and the superior H_(2)-evolution reaction on self-adsorbed S_(2-)ions.In addition,the S^(2-)-adsorbed Mo Sx nanoparticles can also act as the general H_(2)-generation cocatalyst to obviously promote the activity of other typical host photocatalysts such as g-C_(3) N_(4) and Cd S.This work provides an innovative approach to develop high-efficiency Mo Sx-based cocatalyst with boosted interfacial charge transfer toward highly efficient photocatalytic materials.
