Progress and prospects of high-pressure CO2 electrocatalytic reduction

Abstract

Electrochemical CO₂ reduction reaction (eCO₂RR) is highly promising, since it could remove CO₂ emissions, convert them into valuable carbon-based chemicals/fuels, and provide an efficient pathway to utilize renewable electricity. However, there are still unsolved issues including carbonate/bicarbonate salt precipitation, significant hydrogen evolution side reaction (by-HER), instability, etc., which greatly compromise the carbon conversion efficiency, eCO₂RR selectivity and durability, and thus hinder its industrialization. Recent research indicates that increasing CO₂ partial pressure could enhance the surface coverage of CO₂ and intermediates on the catalyst, thereby suppressing the by-HER, improving the reaction rate, enhancing the energy conversion efficiency by reducing driving potentials, and increasing carbon conversion efficiency by reducing the concentration of applied alkaline metal ions in electrolytes. This review discusses the historical development and current progress of high-pressure eCO₂RR technology, especially the electrocatalysts, reaction mechanisms and microenvironments under high-pressure conditions. The application of high pressure in non-aqueous systems and other gas-consuming electrochemical reactions is also summarized. Finally, an outlook on future research in this field is offered, with the aim of advancing high-pressure eCO₂RR from lab-scale research, to pilot design and eventually industrialization.