The electrochemical reduction of N into NH production under ambient conditions represents an attractive prospect for the fixation of N . However, this process suffers from low yield rate of NH over reported electrocatalysts. In this work, a record-high activity for N electrochemical reduction over Ru single atoms distributed on nitrogen-doped carbon (Ru SAs/N-C) is reported. At -0.2 V versus reversible hydrogen electrode, Ru SAs/N-C achieves a Faradaic efficiency of 29.6% for NH production with partial current density of -0.13 mA cm . Notably, the yield rate of Ru SAs/N-C reaches 120.9 μgNH3  mgcat.-1  h-1, which is one order of magnitude higher than the highest value ever reported. This work not only develops a superior electrocatalyst for NH production, but also provides a guideline for the rational design of highly active and robust single-atom catalysts.

As electron transfer to CO is generally considered to be the critical step during the activation of CO , it is important to develop approaches to engineer the electronic properties of catalysts to improve their performance in CO electrochemical reduction. Herein, we developed an efficient strategy to facilitate CO activation by introducing oxygen vacancies into electrocatalysts with electronic-rich surface. ZnO nanosheets rich in oxygen vacancies exhibited a current density of -16.1 mA cm with a Faradaic efficiency of 83 % for CO production. Based on density functional theory (DFT) calculations, the introduction of oxygen vacancies increased the charge density of ZnO around the valence band maximum, resulting in the enhanced activation of CO . Mechanistic studies further revealed that the enhancement of CO production by introducing oxygen vacancies into ZnO nanosheets originated from the increased binding strength of CO and the eased CO activation.

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