Abstract
Electrochemical nitrate reduction to NH3 holds a great promise for N-upcycling in nature,while its slug-gish reaction kinetics involved in both the stepwise deoxygenation and hydrogenation processes necessitates the development of bespoke catalysts with multi-site engineering.Herein,we report a hybrid catalyst composed of rare-earth(RE)yttrium(Y)single atoms and copper phosphide(Cu3P)nanoparticles loaded on N,P-doped carbon(YSA-Cu3P/CNP)through a chelating and pyrolysis method.Owing to a synergistic contribution of Y single atoms and Cu3P nanoparticles,YSA-Cu3P/CNP achieves an impressive NH3 Faradaic efficiency(FE)of 92％at-0.5 V(vs.RHE)and the highest NH3 yield rate of 11.4 mg·h-1·cm-2 at-0.6 V(vs.RHE)in an alkaline media,which surpass most of the reported electrocatalysts.The intricate reaction pathway has been explored by online differential electrochemical mass spectrometry(DEMS),and the synergistic effect between Y single atoms and Cu3P nanoparticles has been studied by in situ synchrotron X-ray absorption spectroscopy.Moreover,density-functional theory(DFT)calculations unveil that the high-efficiency nitrate reduction on YSA-Cu3P/CNP is attributed to a reduced energy barrier of the rate-determining deoxy-genation step coupled with the enhanced stabilization of active hydrogen favorable for the hydrogenation steps,thereby boosting the overall reaction rates.In addition,a prototype Zn-nitrate battery utilizing YSA-Cu3P/CNP as the cathode is unveiled.This work not only elucidates the mechanism behind the enhanced catalytic performance but also paves the way for the future development of high-efficiency electrocatalysts through dual-site engineering.
维普
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