A Unique Gas-Migration, Trapping, and Emitting Strategy for High-Loading Single Atomic Cd Sites for Carbon Dioxide Electroreduction.

Wang, Shuguang; Zhou, Peng; Zhou, Lei; Lv, Fan; Sun, Yingjun; Zhang, Qinghua; Gu, Lin; Yang, Huai et al. · Nano Lett · 2021

basic_science · Level V

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Abstract

Single-atom catalysts (SACs) exhibit great potential in heterogeneous catalysis. However, the achievement of obtaining high-loading SACs remains a bottleneck. Herein, we first demonstrate a unique gas-migration, trapping, and emitting strategy for building a kind of Cd-based SAC for CO<sub>2</sub> reduction (CO<sub>2</sub>RR). The gas-migration and trapping processes (≤750 °C) endows the material with an ultrahigh Cd loading amount of 30.3 wt %, while the emitting process can facilely modulate the loading amount from 30.3 to 1.4 wt %. For the CO<sub>2</sub>RR, the Cd-NC SACs with a loading amount of 18.4 wt % exhibits the maximum Faraday efficiency of 91.4% for CO at -0.728 V. The operando infrared spectroscopy studies prove the presence of main intermediates *COO<sup>-</sup>, *COOH, and *CO on Cd-NC-5M SACs during the catalytic process, indicating that the CO<sub>2</sub>RR follows the proton-decoupled electron-transfer mechanism. Density functional theory simulations reveal that the Cd-N<sub>4</sub> structure reduces the Gibbs free energy of the rate-determining step (the hydrogenation step of *COOH).