A comprehensive review of electrochemical reduction of CO2 to methanol: Technical and design aspects

The electrochemical reduction of CO2 (ERC) is a promising CO2 utilization technology that can convert CO2 into a wide variety of fuels and chemicals via electrochemical reactions. Among the various products that can be produced from ERC, methanol is a potential liquid product that can be utilized as fuel and an intermediate feedstock for fuel and chemical production. Recently, many researchers have shown interest in the ERC process for selective methanol production. The development of ERC technology for methanol production has been done both in experimental studies, particularly electrocatalyst design and development, and in process design and analysis to overcome challenges such as low CO2 solubility, low product selectivity, inefficient catalysts, mass transfer limitations, high overpotentials, and technology commercialization. This review aims to present progress in studies on the production of methanol via ERC. An overview of the CO2 conversion process involving CO2 hydrogenation, ERC, and CO2 photoelectrochemical reduction is first described. Then, key factors affecting the ERC, such as the electrocatalyst, electrolyte, and operating conditions, are analyzed. Furthermore, process design and modeling analyses are discussed to consider the commercialization of the ERC to form methanol. Finally, suggestions for future research are given in the final section of this review.