Cooperative coupling of photocatalytic hydrogen generation with oxidative organic synthesis is promising in simultaneously producing sustainable energy and value-added chemicals.However,the photocatalytic activity is ...Cooperative coupling of photocatalytic hydrogen generation with oxidative organic synthesis is promising in simultaneously producing sustainable energy and value-added chemicals.However,the photocatalytic activity is constrained by restricted redox potentials and insufficient photocarrier separation and transfer.Herein,we construct S-scheme heterojunctions based on metal-doped ZnIn2S4 and covalent organic frameworks,denoted as M-ZIS/TpPa-1(M=Ni or Mo).Theoretical calculations demonstrated that Mo-ZIS possess optimum H adsorption Gibbs free energies,deeper downshift of sulfur p-band center and higher integrated crystal orbital Hamilton population(ICOHP)value than Ni-ZIS and ZIS to optimize H adsorption/desorption dynamics.Besides,metal-doping reasonably enhanced the interfacial charge transfer in heterostructures,identifying the enlarged internal electric field(IEF)in Mo-ZIS/TpPa-1 than Ni-ZIS/TpPa-1 and ZIS/TpPa-1.Moreover,experimental explorations of photoelectrochemical measurements,femtosecond transient absorption spectroscopy,in-situ irradiated X-ray photoelectron spectroscopy and electron paramagnetic resonance verified the facilitated photocarrier separation and migration in metal-doped S-scheme heterojunctions.Ultimately,Mo0.01-ZIS/TpPa-1 exhibited visible-light driven H2 evolution rate of 1648μmol g-1 h-1 and N-benzylidenebenzylamine formation rate of 1812μmol g-1 h-1,better than Ni0.048-ZIS/TpPa-1,and superior to parent ZIS/TpPa-1.This work might provide insights into the modulation of H adsorption/desorption behavior and IEF within S-scheme heterostructures via rational metal-doping strategy for efficient dual-functional photocatalysis.展开更多
The problem of water and sulfur poisoning in flue gas atmosphere remains a significant obstacle for low-temperature deNOx catalysts.This study investigated the sulfation mechanism of the CoMn2O4/CeTiOx(CMC...The problem of water and sulfur poisoning in flue gas atmosphere remains a significant obstacle for low-temperature deNOx catalysts.This study investigated the sulfation mechanism of the CoMn2O4/CeTiOx(CMCT)catalyst during the selective catalytic reduction of NOx with NH3 under conditions containing H2O and SO2 at 150℃.Employing a comprehensive suite of time-resolved analysis and characterization techniques,the evolution of sulfate species was systematically categorized into three stages:initial rapid surface sulfate accumulation,the transformation of surface sulfates to bulk metal sulfates,and partial sulfates decomposition after the removal of H2O and SO2.These findings indicate that bulk metal sulfates irreversibly deactivate the catalyst by distorting active component lattices and consuming oxygen vacancies,whereas surface sulfates(including ammonium sulfates and surface-coordinated metal sulfates)cause reversible performance loss through decomposition.Furthermore,the competitive adsorption of H2O and SO2 significantly influences the catalytic efficiency,with H2O suppressing SO2 adsorption while simultaneously enhancing the formation of Brönsted acid sites.This research underscores the critical role of sulfate dynamics on catalyst performance,revealing the enhanced SO2 resistance of the Eley-Rideal mechanism facilitated by the Ce-Ti support relative to the Langmuir-Hinshelwood pathway.Collectively,the study unravels the complex interplay of sulfate dynamics influencing catalyst performance and provides potential approaches to mitigate deactivation in demanding atmospheric conditions.展开更多
摘要Cooperative coupling of photocatalytic hydrogen generation with oxidative organic synthesis is promising in simultaneously producing sustainable energy and value-added chemicals.However,the photocatalytic activity is constrained by restricted redox potentials and insufficient photocarrier separation and transfer.Herein,we construct S-scheme heterojunctions based on metal-doped ZnIn2S4 and covalent organic frameworks,denoted as M-ZIS/TpPa-1(M=Ni or Mo).Theoretical calculations demonstrated that Mo-ZIS possess optimum H adsorption Gibbs free energies,deeper downshift of sulfur p-band center and higher integrated crystal orbital Hamilton population(ICOHP)value than Ni-ZIS and ZIS to optimize H adsorption/desorption dynamics.Besides,metal-doping reasonably enhanced the interfacial charge transfer in heterostructures,identifying the enlarged internal electric field(IEF)in Mo-ZIS/TpPa-1 than Ni-ZIS/TpPa-1 and ZIS/TpPa-1.Moreover,experimental explorations of photoelectrochemical measurements,femtosecond transient absorption spectroscopy,in-situ irradiated X-ray photoelectron spectroscopy and electron paramagnetic resonance verified the facilitated photocarrier separation and migration in metal-doped S-scheme heterojunctions.Ultimately,Mo0.01-ZIS/TpPa-1 exhibited visible-light driven H2 evolution rate of 1648μmol g-1 h-1 and N-benzylidenebenzylamine formation rate of 1812μmol g-1 h-1,better than Ni0.048-ZIS/TpPa-1,and superior to parent ZIS/TpPa-1.This work might provide insights into the modulation of H adsorption/desorption behavior and IEF within S-scheme heterostructures via rational metal-doping strategy for efficient dual-functional photocatalysis.
摘要The problem of water and sulfur poisoning in flue gas atmosphere remains a significant obstacle for low-temperature deNOx catalysts.This study investigated the sulfation mechanism of the CoMn2O4/CeTiOx(CMCT)catalyst during the selective catalytic reduction of NOx with NH3 under conditions containing H2O and SO2 at 150℃.Employing a comprehensive suite of time-resolved analysis and characterization techniques,the evolution of sulfate species was systematically categorized into three stages:initial rapid surface sulfate accumulation,the transformation of surface sulfates to bulk metal sulfates,and partial sulfates decomposition after the removal of H2O and SO2.These findings indicate that bulk metal sulfates irreversibly deactivate the catalyst by distorting active component lattices and consuming oxygen vacancies,whereas surface sulfates(including ammonium sulfates and surface-coordinated metal sulfates)cause reversible performance loss through decomposition.Furthermore,the competitive adsorption of H2O and SO2 significantly influences the catalytic efficiency,with H2O suppressing SO2 adsorption while simultaneously enhancing the formation of Brönsted acid sites.This research underscores the critical role of sulfate dynamics on catalyst performance,revealing the enhanced SO2 resistance of the Eley-Rideal mechanism facilitated by the Ce-Ti support relative to the Langmuir-Hinshelwood pathway.Collectively,the study unravels the complex interplay of sulfate dynamics influencing catalyst performance and provides potential approaches to mitigate deactivation in demanding atmospheric conditions.