Investigation of CO2 electrochemical reduction to syngas on Zn/Ni-based electrocatalysts using the cyclic voltammetry method

Abstract

The electrochemical CO2 reduction reaction (CO2RR) has been studied on various electrocatalysts including Zn, Ni, Zn0.65-Ni0.35, and Zn0.7-Ni0.2-Co0.1, in 0.1 M of KCl cathodic solution by the cyclic voltammetry (CV) method. The CV measurements for the CO2RR showed that the Zn–Ni bimetallic electrocatalyst has a current density of 8.4 mA cm−2 and overpotential of −130 mV vs. Ag/AgCl. The gas chromatography results presented that the Zn–Ni bimetallic electrocatalyst produced an appropriate amount and ratio of CO (55%) and H2(45%) among other electrocatalysts in this study. SEM and EDX results demonstrated that after 48 h of testing for the CO2RR, the Zn–Ni electrocatalyst had the lowest coke formation among the other electrocatalysts. The microstructure of electrocatalyst for the CO2RR plays a key role, so in this respect, the cluster microstructure of the Zn–Ni electrocatalyst has a more suitable performance than the Zn–Ni–Co electrocatalyst with spherical microstructure. Since the cluster microstructure of Zn–Ni provides more catalyst activation points for the electrocatalyst and less binding energy with intermediate molecules for CO2RR, therefore it is still effective for CO2RR after 48 h, with low coke formation and high efficiency.