Switching Electrocatalytic Hydrogen Evolution Pathways through Electronic Tuning of Copper Porphyrins
Xinyang Peng, Mengchun Zhang, Haonan Qin, Jinxiu Han, Yuhan Xu, Wenzi Li, Xuepeng Zhang, Wei Zhang, Ulf‐Peter Apfel, Rui Cao
Abstract
Abstract The electronic structure of metal complexes plays key roles in determining their catalytic features. However, controlling electronic structures to regulate reaction mechanisms is of fundamental interest but has been rarely presented. Herein, we report electronic tuning of Cu porphyrins to switch pathways of the hydrogen evolution reaction (HER). Through controllable and regioselective β ‐oxidation of Cu porphyrin 1 , we synthesized analogues 2–4 with one or two β ‐lactone groups in either a cis or trans configuration. Complexes 1–4 have the same Cu‐N 4 core site but different electronic structures. Although β ‐oxidation led to large anodic shifts of reductions, 1–4 displayed similar HER activities in terms of close overpotentials. With electrochemical, chemical and theoretical results, we show that the catalytically active species switches from a Cu I species for 1 to a Cu 0 species for 4 . This work is thus significant to present mechanism‐controllable HER via electronic tuning of catalysts.