Enhancing Electrochemical Nitrate Reduction to Ammonia over Cu Nanosheets via Facet Tandem Catalysis
Yunfan Fu, Shuo Wang, Yi Wang, Pengfei Wei, Jiaqi Shao, Tianfu Liu, Guoxiong Wang, Xinhe Bao
Abstract
Abstract Electrochemical conversion of nitrate (NO 3 − ) into ammonia (NH 3 ) represents a potential way for achieving carbon‐free NH 3 production while balancing the nitrogen cycle. Herein we report a high‐performance Cu nanosheets catalyst which delivers a NH 3 partial current density of 665 mA cm −2 and NH 3 yield rate of 1.41 mmol h −1 cm −2 in a flow cell at −0.59 V vs. reversible hydrogen electrode. The catalyst showed a high stability for 700 h with NH 3 Faradaic efficiency of ≈88 % at 365 mA cm −2 . In situ spectroscopy results verify that Cu nanosheets are in situ derived from the as‐prepared CuO nanosheets under electrochemical NO 3 − reduction reaction conditions. Electrochemical measurements and density functional theory calculations indicate that the high performance is attributed to the tandem interaction of Cu(100) and Cu(111) facets. The NO 2 − generated on the Cu(100) facets is subsequently hydrogenated on the Cu(111) facets, thus the tandem catalysis promotes the crucial hydrogenation of *NO to *NOH for NH 3 production.