Tailoring Microenvironment in Bilayer Electrode with Copper and Silver Nanocatalysts for Bicarbonate Electroreduction to Multicarbon Products

Abstract

As compared with CO2 electrolyzers, bicarbonate electrolyzers can achieve direct conversion of CO2 captured solutions to higher-valued chemicals, that can bypass energy-intensive steps of CO2 regeneration and pressurization processes. However, most previous studies have only reported single carbon chemicals (i.e., CO, formate, CH4) as the major products so far. In this presentation, we will present direct electro-reduction of potassium bicarbonate (KHCO3) to multicarbon (C2+) products (i.e., acetate, ethylene, ethanol, propanol) using rationally designed bilayer of Cu and Ag nanosized catalysts. The in-situ generated CO2 was first reduced to CO on the Ag layer, followed by CO reduction to C2+ products on the Cu layer benefiting from locally high concentration of CO. Through optimizing the configurations, compositions, ionomer types, and local hydrophobicity of the bilayer electrode, we have created the favorable microenvironment (high local pH, low water content, etc.) to increase bicarbonate conversion to C2+ products with a largely suppressed hydrogen evolution reaction, and a remarkable C2+ FE of 41.6% at a current density of 100 mA cm−2 was achieved.