Aqueous CO2 Reduction by a Re(bipyridine)-polypyrrole Film Deposited on Colloid-Imprinted Carbon

摘要

Herein, we report a [Re(bipyridine)]-carbon hybrid material for efficient and selective CO_(2) to CO conversion in water. The Re catalyst was incorporated into a nanoporous colloid-imprinted carbon (CIC) powder by an electrochemical polymerization method. Uniform [Re(bipyridine)]-containing polymer films were formed on the carbon surface, where the catalyst-polymer loading could be controlled by varying the polymerization parameters. Thorough pre- and post-catalysis characterization confirmed the integrity of the [Re(bpy)] CO_(2) reduction catalyst. CIC|poly [Re] electrodes reduced CO_(2) to CO in 0.5 M CO_(2)-saturated KHCO_(3) electrolyte solution at E _(appl.) = ?0.66 V versus reversible hydrogen electrode (RHE) (η = 550 mV), with initial Faradaic efficiencies for CO formation (FE_(CO)) between 88 and 100%. Higher catalyst loadings generally yielded higher FE_(CO) and better long-term stability under catalytic conditions, producing CO and maintaining selectivity of above 70% for a period of at least 24 h for the hybrid material with the highest [Re(bipyridine)] polymer loading. While electrochemical analyses suggested some electron and mass transport issues on shorter timescales, these were not confirmed in long-term electrolysis. Our work highlights the great applicability of (electro)polymerization techniques in combination with nanoporous CIC to prepare hybrid materials for energy conversion.