Radiolytic approach for efficient, selective and catalyst‐free CO2 conversion at room temperature

The present study proposes a new approach for direct CO 2 conversion using primary radicals from water irradiation. In order to ensure reduction of CO 2 into CO 2 •- by all the hydrated electrons, we use formate ions to scavenge simultaneously the parent oxidizing radicals H • and OH • producing the same transient CO 2 •- radicals. Conditions are optimized to obtain the highest conversion yield of CO 2 . The goal is achieved under mild conditions of room temperature, neutral pH and 1 atm of CO 2 pressure. All the available radicals are exploited for selectively converting CO 2 into oxalate that is accompanied by H 2 evolution. Besides, at high CO 2 pressure, CO is also produced via presolvated electron scavenging and the H • radicals with CO 2 •- . 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 CO 2 capture at the source in industry and the products, oxalate salt and H 2 , can be easily separated.