Exploring the frontiers of electrochemical CO2 conversion: A comprehensive review

Abstract

The electrochemical conversion of carbon dioxide into valuable products is pivotal for maintaining the global carbon cycle and mitigating global warming. This review explores the advancements in electrochemical CO₂ conversion, particularly focusing on producing methanol, ethanol, and n-propanol using various catalysts such as metals, metal oxides, metal alloys, and metal organic frameworks. Additionally, it covers the photoelectrochemical (PEC) conversion of CO₂ into alcohols. The primary objective is to identify efficient electrocatalysts for ethanol, methanol, and n-propanol production, prioritizing selectivity, stability, Faradaic efficiency (FE), and current density. Notable catalysts include Pt_xZn nanoalloys, which exhibit an FE of ∼81.4 ​% for methanol production, and trimetallic Pt/Pb/Zn nanoalloys, aimed at reducing Pt costs while enhancing catalyst stability and durability. Metal oxide catalysts like thin film Cu₂O/CuO on nickel foam and Cu₂O/ZnO achieve FE values of ∼38 ​% and ∼16.6 ​% for methanol production, respectively. Copper-based metal-organic frameworks, such as Cu@ Cu₂O, demonstrate an FE of ∼45 ​% for methanol production. Similarly, Ag_0.14/Cu_0.86 and Cu–Zn alloys exhibit FEs of ∼63 ​% and ∼46.6 ​%, respectively, for ethanol production. Notably, n-propanol production via Pd–Cu alloy and graphene/ZnO/Cu₂O yields FEs of ∼13.7 ​% and ∼23 ​%, respectively. Furthermore, the review discusses recent advancements in PEC reactor design, photoelectrodes, reaction mechanisms, and catalyst durability. By evaluating the efficiency of these devices in liquid fuel production, the review addresses challenges and prospects in CO₂ conversion for obtaining various valuable products.