Enhanced Electrocatalytic Activity of a Zinc Porphyrin for CO<sub>2</sub> Reduction: Cooperative Effects of Triazole Units in the Second Coordination Sphere
Amir Lashgari, Caroline K. Williams, Jenna L. Glover, Yueshen Wu, Jingchao Chai, Jianbing Jiang
Abstract
Abstract The control of the second coordination sphere in a coordination complex plays an important role in improving catalytic efficiency. Herein, we report a zinc porphyrin complex ZnPor8T with multiple flexible triazole units comprising the second coordination sphere, as an electrocatalyst for the highly selective electrochemical reduction of carbon dioxide (CO 2 ) to carbon monoxide (CO). This electrocatalyst converted CO 2 to CO with a Faradaic efficiency of 99 % and a current density of −6.2 mA cm −2 at −2.4 V vs. Fc/Fc + in N , N ‐dimethylformamide using water as the proton source. Structure‐function relationship studies were carried out on ZnPor8T analogs containing different numbers of triazole units and distinct triazole geometries; these unveiled that the triazole units function cooperatively to stabilize the CO 2 ‐catalyst adduct in order to facilitate intramolecular proton transfer. Our findings demonstrate that incorporating triazole units that function in a cooperative manner is a versatile strategy to enhance the activity of electrocatalytic CO 2 conversion.