Ammonia production via electrochemical nitrate reduction is essential for environmental protection and the emerging hydrogen economy. Complex nitrate wastewater with a wide pH range calls for flexible catalysts with h...Ammonia production via electrochemical nitrate reduction is essential for environmental protection and the emerging hydrogen economy. Complex nitrate wastewater with a wide pH range calls for flexible catalysts with high selectivity. A high Faradaic efficiency(FE) of NH3 cannot be obtained under strong acid or alkaline conditions due to the uncontrollable adsorption energy and coverage of hydrogen species(H*) on active sites. This article describes the design and fabrication of a copper-palladium(Cu-Pd) alloy nanocrystal catalyst that inhibits H2 and nitrite generation in electrolytes with different nitrate concentrations and varied pH. The interfacial sites of Cu-Pd alloys could enhance the adsorption energy and coverage of H* while increasing the reaction rate constant of NO_(2)*-to-NO*, which achieves a rapid conversion of NO_(2)* along with a decreased FE of NO_(2)-. Under ambient conditions, optimal FE(NH3) is close to 100% at a wide pH range, with the solar-to-chemical conversion efficiency approaching 4.29%. The combination of thermodynamics and kinetics investigations would offer new insights into the reduction mechanism of NO_(2)* for further development of nitrate reduction.展开更多
基金supported by the National Key R&D Program of China(2021YFA1500804)the National Natural Science Foundation of China(22121004,51861125104)+1 种基金the Natural Science Foundation of Tianjin City(18JCJQJC47500)Haihe Laboratory of Sustainable Chemical Transformations,the Program of Introducing Talents of Discipline to Universities(BP0618007)and the Xplorer Prize.
文摘Ammonia production via electrochemical nitrate reduction is essential for environmental protection and the emerging hydrogen economy. Complex nitrate wastewater with a wide pH range calls for flexible catalysts with high selectivity. A high Faradaic efficiency(FE) of NH3 cannot be obtained under strong acid or alkaline conditions due to the uncontrollable adsorption energy and coverage of hydrogen species(H*) on active sites. This article describes the design and fabrication of a copper-palladium(Cu-Pd) alloy nanocrystal catalyst that inhibits H2 and nitrite generation in electrolytes with different nitrate concentrations and varied pH. The interfacial sites of Cu-Pd alloys could enhance the adsorption energy and coverage of H* while increasing the reaction rate constant of NO_(2)*-to-NO*, which achieves a rapid conversion of NO_(2)* along with a decreased FE of NO_(2)-. Under ambient conditions, optimal FE(NH3) is close to 100% at a wide pH range, with the solar-to-chemical conversion efficiency approaching 4.29%. The combination of thermodynamics and kinetics investigations would offer new insights into the reduction mechanism of NO_(2)* for further development of nitrate reduction.
