Promoting Dinuclear-Type Catalysis in Cu<sub>1</sub> -C<sub>3</sub> N<sub>4</sub> Single-Atom Catalysts.

Song, Jingting; Chen, Zhongxin; Cai, Xiangbin; Zhou, Xin; Zhan, Gaolei; Li, Runlai; Wei, Pingping; Yan, Ning et al. · Adv Mater · 2022

basic_science · Level V

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Abstract

Reducing particle size in supported metal catalysts to single-atom level isolates the active metal sites and maximizes the atomic utilization efficiency. However, the large inter-atom distance, particularly in low-loading single-atom catalyst (SAC), is not favorable for a complex reaction where two (or more) reactants have to be activated. A key question is how to control the inter-atom distances to promote dinuclear-type coactivation at the adjacent metal sites. Here, it is reported that reducing the average inter-atom distance of copper SACs supported on carbon nitride (C<sub>3</sub> N<sub>4</sub> ) to 0.74 ± 0.13 nm allows these catalysts to exhibit a dinuclear-type catalytic mechanism in the nitrile-azide cycloaddition. Operando X-ray absorption fine structure study reveals a dynamic ligand exchange process between nitrile and azide, followed by their coactivation on dinuclear Cu SAC sites to form the tetrazole product. This work highlights that reducing the nearest-neighbor distance of SAC allows the mechanistic pathway to diversify from single-site to multisite catalysis.