Cu–phen Coordination Enabled Selective Electrocatalytic Reduction of CO<sub>2</sub> to Methane
Haiyan Hu, Shiting Qian, Qin Shi, Minxing Du, Ning Sun, Yong Ding, Jun Li, Qiquan Luo, Zhen Li, Lin He, Yuxia Sun, Yuehui Li
Abstract
Manipulation of selectivity in the catalytic electrochemical carbon dioxide reduction reaction (eCO 2 RR) poses significant challenges due to inevitable structure reconstruction. One approach is to develop effective strategies for controlling reaction pathways to gain a deeper understanding of mechanisms in robust CO 2 RR systems. In this work, by precise introduction of 1,10-phenanthroline as a bidentate ligand modulator, the electronic property of the copper site was effectively regulated, thereby directing selectivity switch. By modification of [Cu 3 (btec)(OH) 2 ] n, the use of [Cu 2 (btec)(phen) 2 ] n ·(H 2 O) n achieved the selectivity switch from ethylene (faradaic efficiency (FE) = 41%, FE C2+ = 67%) to methane (FE CH 4 = 69%). Various in situ spectroscopic characterizations revealed that [Cu 2 (btec)(phen) 2 ] n ·(H 2 O) n promoted the hydrogenation of *CO intermediates, leading to methane generation instead of dimerization to form C 2+ products. Acting as a delocalized π-conjugation scaffold, 1,10-phenanthroline in [Cu 2 (btec)(phen) 2 ] n ·(H 2 O) n helps stabilize Cu δ+ . This work presents a novel approach to regulate the coordination environment of active sites with the aim of selectively modulating the CO 2 RR.