Understanding the impact of reaction parameters on electrochemical reduction of CO2 to methanol: Activity relationship of cuprite@polyaniline electrodes

Abstract

The carbon dioxide reduction reaction (CO2RR) is a key reaction that efficiently uses CO2 to produce value-added chemicals. However, the main limitation of this reaction is its low selectivity which results in the formation of a variety of by-products. As a result, the current challenge for CO2RR is the efficient formation of product with high Faradaic efficiency (FE). Our main goal is to replace precious metal electrocatalysts with more abundant transition metal/conducting support hybrid catalysts. Herein, we’ve synthesized a cuprite-polyaniline (Cu2O@PANI) composites. The superior catalytic activity in terms of activity and selectivity for methanol (MeOH) synthesis could be attributed to the synergism between Cu2O and PANI that enables it to scale back multiple species, higher electrical conductivity, and lowest resistance during the charge/mass transfer processes. These properties were confirmed using Electrochemical impedance spectroscopy (EIS), Electron transfer rate constant (Ks), Mott-Schottky (MS), Double-layer capacitance (DLC), and Density-functional theory (DFT) analysis. Based on these findings Cu2O@PANI matrix easily forms many intermediate (CO) species and maintains a higher CO2 concentration around the electrode surface throughout the experiment. The results of the given electrocatalytic system show that the Cu2O@PANI matrix significantly suppressed the by-product throughout the experiment, resulting in MeOH (45.21%) FE within 90 min. Given these benefits, the catalytic system is appropriate for CO2RR.