Wide-pH-range adaptable ammonia electrosynthesis from nitrate on Cu-Pd interfaces  

作　　者：Yongtao Wang Peng Zhang Xiaoyun Lin Gong Zhang Hui Gao Qingzhen Wang Zhi-Jian Zhao Tuo Wang Jinlong Gong 

机构地区：[1]Key Laboratory for Green Chemical Technology of Ministry of Education,School of Chemical Engineering and Technology,Tianjin University,Tianjin 300072,China [2]Collaborative Innovation Center of Chemical Science and Engineering,Tianjin 300072,China [3]Haihe Laboratory of Sustainable Chemical Transformations,Tianjin 300192,China [4]Joint School of National University of Singapore and Tianjin University,International Campus of Tianjin University,Binhai New City,Fuzhou 350207,China

出　　处：《Science China Chemistry》2023年第3期913-922,共10页中国科学（化学英文版）

基　　金：supported by the National Key R&D Program of China(2021YFA1500804);the National Natural Science Foundation of China(22121004,51861125104);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.

摘　　要：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.

关 键 词：nitrate reduction ammonia synthesis Cu-Pd interfaces reaction kinetics break p H limitation 

分 类 号：TG1[金属学及工艺—金属学]