Recent advances in the possible electrocatalysts for the electrochemical reduction of carbon dioxide into methanol

Abstract

The world is dependent on fossil-fuel-based energy systems, which constantly release carbon dioxide (CO2) gas into the atmosphere. This poses a significant threat to the global environmental balance. Currently, there are various potential ways to alter the CO2 concentration in the atmosphere or prevent the release of CO2, including the commercial use of CO2 in various chemical reactions, as well as CO2 capture and sequestration technology. Concerning the latter, electrochemical CO2 reduction (ECO2R) could be used to convert CO2 into value-added chemicals, such as formic acid, carbon monoxide, ethanol, and methanol, and this method has drawn the interest of many researchers. Methanol is one of the products of the ECO2R reaction, and direct methanol fuel cells are emerging energy sources with a wide range of applications. However, the design and engineering of highly efficient electrocatalysts for ECO2R are crucial to accelerate the development of this field. In this review, we highlight systematic studies on promising ECO2R electrocatalysts, such as those based on copper and molybdenum and their derivative compounds, as well as monometallic/bi-metallic, metals–organic complexes, precious metals, and single-atom electrocatalysts, reported so far. The current understanding of the ECO2R mechanism and the trends in the activities of various electrocatalysts are also summarized. Overall, this review article summarizes the attempts and outcomes of ECO2R for methanol formation over various electrocatalyst surfaces. Additionally, we present some of our own perspectives on future challenges in this field.