清华大学王定胜团队报道了MOF包封N-杂环卡宾铜单原子位催化剂用于高效电合成甲烷。相关研究成果发表在2021年11月12日出版的《德国应用化学》。

开发高效二氧化碳还原（CO₂RR）电催化剂用于甲烷（CH4）电合成已成为间歇式可再生电力储存的热点，但仍然存在挑战。

该文报道了N-杂环卡宾（NHC）-配体铜单原子位（Cu-SAS）嵌入金属有机框架中（20Bn-Cu@UiO-67），在-1.5 V vs RHE，电流密度为420 mA cm^-2的情况下,CO₂还原为CH4时，可实现81%的出色法拉第效率（FE）。值得注意的是，该催化剂的CH4 FE在很大的电压范围内保持在70%以上，并且达到了前所未有的16.3 s^-1的转换频率（TOF），这几乎代表了迄今为止CH4电合成的最佳分子催化剂。

实验结果表明，NHC的σ赋能提高了Cu-SAS的表面电子密度，促进了CHO*中间体的优先吸附。同时，催化剂的孔隙率促进了CO₂向2Bn-Cu的扩散，从而显著提高了每个催化中心的可用性。该NHC连接的Cu-SAS催化剂设计在CH4电合成中具有很大的优势，为CH4的商业化生产提供了思路。

附：英文原文

Title: MOF Encapsulating N-Heterocyclic Carbene-Ligated Copper Single-Atom Site Catalyst towards Efficient Methane Electrosynthesis

Author: Shenghua Chen, Wen-Hao Li, Wenjun Jiang, Jiarui Yang, Jiexin Zhu, Liqiang Wang, Honghui Ou, Zechao Zhuang, Mingzhao Chen, Xiaohui Sun, Dingsheng Wang, Yadong Li

Issue&Volume: 2021-11-12

Abstract: The exploitation of highly efficient carbon dioxide reduction (CO2RR) electrocatalyst for methane (CH4) electrosynthesis has attracted great attention for the intermittent renewable electricity storage, but remain challenges. Here, N-heterocyclic carbene (NHC)-ligated Copper single atom site (Cu SAS) embedded in metal organic framework is reported (2Bn-Cu@UiO-67), which can achieve an outstanding Faradaic efficiency (FE) of 81% for the CO2 reduction to CH4 at -1.5 V vs RHE with a current density of 420 mA cm-2. Notably, the CH4 FE of our catalyst remains above 70% within a wide potential range, and achieves an unprecedented turnover frequency (TOF) of 16.3 s-1, which almost represents the best molecular catalyst for CH4 electrosynthesis to date. The experimental results show that the σ donation of NHC enriches the surface electron density of Cu SAS and promotes the preferential adsorption of CHO* intermediates. Meanwhile, the porosity of the catalyst facilitates the diffusion of CO2 to 2Bn-Cu, thereby significantly increasing the availability of each catalytic center. This NHC-ligated Cu SAS catalyst design has great advantages in CH4 electrosynthesis and provides ideas for the commercial production of CH4.

DOI: 10.1002/anie.202114450

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202114450