Highly selective, catalyst-free CO2 reduction in strong acid without alkali cations by a mechanical energy-induced triboelectric plasma-electrolytic system

Abstract

The electrochemical CO₂ reduction reaction (CO₂RR) in an acidic medium is a promising pathway to produce high-valued commodity chemicals. However, a highly selective CO₂RR in acids cannot be attained due to competing hydrogen evolution reactions (HERs) on the electrocatalyst surface. Here, we demonstrate a hybrid triboelectric plasma-electrochemical system induced by mechanical energy in strong acids associated with a gas–liquid interface triboelectric plasma that triggers CO₂ reduction at room temperature and atmospheric pressure without catalysts or alkali cations. Record-high selectivity of CO (nearly 100%) and energy efficiency from electrical-to-chemical energy of 66.7% are achieved, outperforming the previously reported results for advanced electrocatalytic CO₂RRs. The unprecedented selectivity is attributed to the solvated CO₂⁻ radical anions at the gas triboelectric plasma–liquid interface, which prefers to react with protons to form the key intermediate of COOH. Our findings uncover the potential of a mechanical energy-induced triboelectric plasma-electrochemical process for overcoming the selectivity limitations of electrocatalytic reactions.