Synthesis of various Pb catalysts and their examination in the study of electrochemical CO2 reduction (ECR) using a quartz crystal microbalance with a Mn3O4 anode

Abstract

As increasing CO₂ concentration in the atmosphere seriously harms ecosystems, there is a need to decrease the level of CO₂ to ensure the survival of mankind. Electrochemical CO₂ reduction is considered to be one of the best methods for decreasing the level of atmospheric CO₂. The quartz crystal microbalance (QCM) is widely regarded as an ideal instrument for probing the mass deviations between an aqueous phase and crystal surface with a high sensing ability. In the current study, electrochemical CO₂ reduction (ECR) on synthesized Pb catalysts with a Mn₃O₄ anode using a QCM was investigated. All tests were carried out in a NaHCO₃ electrolyte solution with Pb catalysts on a QCM gold resonator as the cathode and Mn₃O₄ coated graphite as the anode, in order to investigate the frequency and mass change on the Pb catalyst surface. For the first time, the QCM has been studied for use in the ECR reaction on Pb catalysts, and the influence of the Pb catalyst structure on CO₂ reduction in terms of mass and frequency over time has been examined. The experimental findings indicate that the QCM is a very useful tool for monitoring the CO₂ adsorption on the catalysts with respect to the applied voltage. Cyclic voltammetry and chronoamperometry were used to study the activity of the catalysts for CO₂ reduction, and the associated frequencies and mass change at the surface of the QCM are discussed in detail.