CO2 valorisation towards alcohols by Cu-based electrocatalysts: challenges and perspectives

Developing efficient technologies to decrease CO2 emissions and dealing with climate change issues are among the most critical challenges in worldwide research. This review discusses the most recent advances on the electrochemical transformation of CO2 to alcohols, mainly methanol, ethanol and n-propanol, as a promising way to produce renewable liquid fuels. The main focus is given to copperbased electrocatalyst with different structures (Cu nanoparticles, oxide-derived Cu, and Cu composites) because Cu is up to now the heterogeneous catalyst with the most relevant activity for producing valuable C1+ hydrocarbons and alcohols via CO2 co-electrolysis. Several factors that impact the reaction activity and selectivities, such as the catalyst morphology, composition, surface structure, electrolyte effects and the electrocatalytic cell design (including liquid-phase and catholyte-free systems) are considered and analysed. This review reports an overview of the state-of-the-art with the most recent investigation highlights. It aims to provide guidance on the best experimental practices, new research directions, and strategies to develop efficient electrocatalysts. An outlook about the main challenges to be still resolved for a future practical application of this technology is also provided, toward a future based on sustainability and independence from fossil fuels.