The problem of water and sulfur poisoning in flue gas atmosphere remains a significant obstacle for low-temperature deNO_(x) catalysts.This study investigated the sulfation mechanism of the CoMn_(2)O_(4)/CeTiO_(x)(CMC...The problem of water and sulfur poisoning in flue gas atmosphere remains a significant obstacle for low-temperature deNO_(x) catalysts.This study investigated the sulfation mechanism of the CoMn_(2)O_(4)/CeTiO_(x)(CMCT)catalyst during the selective catalytic reduction of NO_(x) with NH3 under conditions containing H2O and SO_(2) 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 SO_(2).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 SO_(2) significantly influences the catalytic efficiency,with H2O suppressing SO_(2) 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 SO_(2) 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
Electrosynthesis of hydrogen peroxide(H2O2)is an on-site method that enables independent distribution applications in many fields due to its small-scale and sustainable features.The crucial point remains developing hi...Electrosynthesis of hydrogen peroxide(H2O2)is an on-site method that enables independent distribution applications in many fields due to its small-scale and sustainable features.The crucial point remains developing highly active,selective and cost-effective electrocatalysts.The electrosynthesis of H2O2 in acidic media is more practical owing to its stability and no need for further purification.We herein report a phosphorus and selenium tuning Co-based non-precious catalyst(CoPSe)toward two-electron oxygen reduction reaction(2e–ORR)to produce H2O2 in acidic media.The starting point of using both P and Se is finding a balance between strong ORR activity of CoSe and weak activity of CoP.The results demonstrated that the CoPSe catalyst exhibited the optimized 2e–ORR activity compared with CoP and CoSe.It disclosed an onset potential of 0.68 V and the H2O2 selectivity 76%-85%in a wide potential range(0–0.5 V).Notably,the CoPSe catalyst overcomes a significant challenge of a narrow-range selectivity for transitionmetal based 2e–ORR catalysts.Finally,combining with electro-Fenton reaction,an on-site system was constructed for efficient degradation of organic pollutants.This work provides a promising non-precious Co-based electrocatalyst for the electrosynthesis of H2O2 in acidic media.展开更多
文摘The problem of water and sulfur poisoning in flue gas atmosphere remains a significant obstacle for low-temperature deNO_(x) catalysts.This study investigated the sulfation mechanism of the CoMn_(2)O_(4)/CeTiO_(x)(CMCT)catalyst during the selective catalytic reduction of NO_(x) with NH3 under conditions containing H2O and SO_(2) 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 SO_(2).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 SO_(2) significantly influences the catalytic efficiency,with H2O suppressing SO_(2) 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 SO_(2) 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.
基金the National Natural Science Foundation of China(Nos.21805052,21974031,2278092)Science and Technology Research Project of Guangzhou(Nos.202102020787 and 202201000002)+2 种基金Department of Science&Technology of Guangdong Province(No.2022A156)Key Discipline of Materials Science and Engineering,Bureau of Education of Guangzhou(No.20225546)the Innovation&Entrepreneurship for the College Students of Guangzhou University(No.XJ202111078175).
文摘Electrosynthesis of hydrogen peroxide(H2O2)is an on-site method that enables independent distribution applications in many fields due to its small-scale and sustainable features.The crucial point remains developing highly active,selective and cost-effective electrocatalysts.The electrosynthesis of H2O2 in acidic media is more practical owing to its stability and no need for further purification.We herein report a phosphorus and selenium tuning Co-based non-precious catalyst(CoPSe)toward two-electron oxygen reduction reaction(2e–ORR)to produce H2O2 in acidic media.The starting point of using both P and Se is finding a balance between strong ORR activity of CoSe and weak activity of CoP.The results demonstrated that the CoPSe catalyst exhibited the optimized 2e–ORR activity compared with CoP and CoSe.It disclosed an onset potential of 0.68 V and the H2O2 selectivity 76%-85%in a wide potential range(0–0.5 V).Notably,the CoPSe catalyst overcomes a significant challenge of a narrow-range selectivity for transitionmetal based 2e–ORR catalysts.Finally,combining with electro-Fenton reaction,an on-site system was constructed for efficient degradation of organic pollutants.This work provides a promising non-precious Co-based electrocatalyst for the electrosynthesis of H2O2 in acidic media.
