Qiu Xiao-Feng, Zhu Hao-Lin, Huang Jia-Run, Liao Pei-Qin, Chen Xiao-Ming
MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China.
J Am Chem Soc. 2021 May 19;143(19):7242-7246. doi: 10.1021/jacs.1c01466. Epub 2021 May 6.
Conversion from CO to CH is important for the development of energy and the environment, but the high energy barrier of hydrogenation of the *CO intermediate and C-C coupling step tend to result in C compounds as the main product and thus restrict the generation of CH. Here, we report a metal-organic framework (denoted as ), composed of 2,3,9,10,16,17,23,24-octahydroxyphthalo-cyaninato)copper(II) (PcCu-(OH)) ligands and the square-planar CuO nodes, as the electrocatalyst for CO to CH. Compared with the discrete molecular copper-phthalocyanine (Faradaic efficiency (FE) of CH = 25%), exhibits much higher performance for electrocatalytic reduction of CO to CH with a FE of 50(1)% and a current density of 7.3 mA cm at the potential of -1.2 V vs RHE in 0.1 M KHCO solution, representing the best performance reported to date. infrared spectroscopy and control experiments suggested that the enhanced electrochemical performance may be ascribed to the synergistic effect between the CuPc unit and the CuO unit, namely the CO on the CO-producing site (CuO site) can efficiently migrate and dimerize with the *CO intermediate adsorbed on the CH-producing site (CuPc), giving a lower C-C dimerization energy barrier.
从一氧化碳（CO）转化为甲烷（CH）对于能源发展和环境保护至关重要，但是CO中间体氢化和碳-碳偶联步骤的高能量壁垒往往导致以含碳化合物作为主要产物，从而限制了CH的生成。在此，我们报道了一种由2,3,9,10,16,17,23,24-八羟基酞菁铜（II）（PcCu-(OH)）配体和平面正方形CuO节点组成的金属有机框架（记为 ），作为将CO转化为CH的电催化剂。与离散的分子型铜酞菁（CH的法拉第效率（FE） = 25%）相比， 在将CO电催化还原为CH方面表现出更高的性能，在0.1 M KHCO溶液中相对于可逆氢电极（RHE）为 -1.2 V的电位下，FE为50(1)%，电流密度为7.3 mA cm ，代表了迄今为止报道的最佳性能。红外光谱和对照实验表明，增强的电化学性能可能归因于CuPc单元和CuO单元之间的协同效应，即CO生成位点（CuO位点）上的CO能够与吸附在CH生成位点（CuPc）上的CO中间体有效地迁移并二聚，给出更低的碳-碳二聚能量壁垒。
