Radiolytic Approach for Efficient, Selective and Catalyst-free CO2 Conversion at Room Temperature

Abstract

The present study proposes a new approach for direct CO₂ conversion using primary radicals from water irradiation. In order to ensure reduction of CO₂ into CO₂^-. by all the primary radiation-induced water radicals, we use formate ions to scavenge simultaneously the parent oxidizing radicals H^. and OH^. producing the same transient CO₂^-. radicals. Conditions are optimized to obtain the highest conversion yield of CO₂ . The goal is achieved under mild conditions of room temperature, neutral pH and 1 atm of CO₂ pressure. All the available radicals are exploited for selectively converting CO₂ into oxalate that is accompanied by H₂ evolution. The mechanism presented accounts for the results and also sheds light on the data in the literature. The radiolytic approach is a mild and scalable route of direct CO₂ capture at the source in industry and the products, oxalate salt and H₂ , can be easily separated.

Keywords: CO2 conversion; CO2 radiolysis; CO2 reduction; Catalyst free; Oxalate.