中山大学廖培钦团队报道了限制在单一金属-有机层中的Dicopper(I)位点在中性电解质中促进CO₂电还原为CH₄。相关研究成果于2023年9月21日发表在国际顶尖学术期刊《美国化学会杂志》。

在中性条件下实现电化学CO₂还原反应（eCO2RR）的高性能以产生CH₄是具有挑战性和重要的。到目前为止，大多数报道的eCO₂RR产生CH₄的活性位点是单金属位点；性能远低于商业要求。

该文中，研究人员报道了一种单层的纳米片金属-有机层，即[Cu₂（obpy）₂]（Cuobpy SL，Hoppy=1H-[2,2′]联吡啶-6-酮），具有eCO₂RR在中性水溶液中产生CH₄的双铜（I）位点。Cuobpy SL的详细检查显示，与可逆氢电极（RHE）相比，在1.4 V下，其CH₄生产性能高，法拉第效率为82（1）%，电流密度为～90 mA c^m–2。在连续运行100小时内没有观察到明显的降解，这代表了迄今为止的显著性能。

机理研究表明，与传统的单铜位点和完全暴露的双铜（I）位点相比，分子堆叠形成的受限空间中的双铜位点对*CO、*CHO和*CH₂O等关键C1中间体具有较强的亲和力，促进了CH₄的产生，但抑制了C–C偶联。

附：英文原文

Title: Dicopper(I) Sites Confined in a Single Metal–Organic Layer Boosting the Electroreduction of CO2 to CH4 in a Neutral Electrolyte

Author: Jin-Meng Heng, Hao-Lin Zhu, Zhen-Hua Zhao, Can Yu, Pei-Qin Liao, Xiao-Ming Chen

Issue&Volume: September 21, 2023

Abstract: It is challenging and important to achieve high performance for an electrochemical CO2 reduction reaction (eCO2RR) to yield CH4 under neutral conditions. So far, most of the reported active sites for eCO2RR to yield CH4 are single metal sites; the performances are far below the commercial requirements. Herein, we reported a nanosheet metal–organic layer in single-layer, namely, [Cu2(obpy)2] (Cuobpy-SL, Hobpy = 1H-[2,2′]bipyridinyl-6-one), possessing dicopper(I) sites for eCO2RR to yield CH4 in a neutral aqueous solution. Detailed examination of Cuobpy-SL revealed high performance for CH4 production with a faradic efficiency of 82(1)% and a current density of ～90 mA cm–2 at 1.4 V vs. reversible hydrogen electrode (RHE). No obvious degradation was observed over 100 h of continuous operation, representing a remarkable performance to date. Mechanism studies showed that compared with the conventional single-copper sites and completely exposed dicopper(I) sites, the dicopper(I) sites in the confined space formed by the molecular stacking have a strong affinity to key C1 intermediates such as *CO, *CHO, and *CH2O to facilitate the CH4 production, yet inhibiting C–C coupling.

DOI: 10.1021/jacs.3c08571

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.3c08571