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Enhanced Nitrate-to-Ammonia Activity on Copper–Nickel Alloys via Tuning of Intermediate Adsorption
journal contribution
posted on 2020-03-12, 13:03 authored by Yuhang Wang, Aoni Xu, Ziyun Wang, Linsong Huang, Jun Li, Fengwang Li, Joshua Wicks, Mingchuan Luo, Dae-Hyun Nam, Chih-Shan Tan, Yu Ding, Jiawen Wu, Yanwei Lum, Cao-Thang Dinh, David Sinton, Gengfeng Zheng, Edward H. SargentElectrochemical
conversion of nitrate (NO3–) into ammonia
(NH3) recycles nitrogen and offers a route
to the production of NH3, which is more valuable than dinitrogen
gas. However, today’s development of NO3– electroreduction remains hindered by the lack of a mechanistic picture
of how catalyst structure may be tuned to enhance catalytic activity.
Here we demonstrate enhanced NO3– reduction reaction (NO3–RR) performance on Cu50Ni50 alloy catalysts, including a 0.12 V upshift in the half-wave potential
and a 6-fold increase in activity compared to those obtained with
pure Cu at 0 V vs reversible hydrogen electrode (RHE). Ni alloying
enables tuning of the Cu d-band center and modulates
the adsorption energies of intermediates such as *NO3–, *NO2, and *NH2. Using density
functional theory calculations, we identify a NO3–RR-to-NH3 pathway and offer an adsorption energy–activity
relationship for the CuNi alloy system. This correlation between catalyst
electronic structure and NO3–RR activity
offers a design platform for further development of NO3–RR catalysts.