Self-Tandem Electrocatalytic NO Reduction to NH<sub>3</sub> on a W Single-Atom Catalyst.

Chen, Kai; Wang, Jiaxin; Zhang, Hu; Ma, Dongwei; Chu, Ke · Nano Lett · 2023

basic_science · Level V

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Abstract

We design single-atom W confined in MoO<sub>3-<i>x</i></sub> amorphous nanosheets (W<sub>1</sub>/MoO<sub>3-<i>x</i></sub>) comprising W<sub>1</sub>-O<sub>5</sub> motifs as a highly active and durable NORR catalyst. Theoretical and operando spectroscopic investigations reveal the dual functions of W<sub>1</sub>-O<sub>5</sub> motifs to (1) facilitate the activation and protonation of NO molecules and (2) promote H<sub>2</sub>O dissociation while suppressing *H dimerization to increase the proton supply, eventually resulting in a self-tandem NORR mechanism of W<sub>1</sub>/MoO<sub>3-<i>x</i></sub> to greatly accelerate the protonation energetics of the NO-to-NH<sub>3</sub> pathway. As a result, W<sub>1</sub>/MoO<sub>3-<i>x</i></sub> exhibits the highest NH<sub>3</sub>-Faradaic efficiency of 91.2% and NH<sub>3</sub> yield rate of 308.6 μmol h<sup>-1</sup> cm<sup>-2</sup>, surpassing that of most previously reported NORR catalysts.