Catholyte‐Free Electrocatalytic CO 2 Reduction to Formate

Electrochemical reduction of carbon dioxide (CO 2 ) into value‐added chemicals is a promising strategy to reduce CO 2 emission and mitigate climate change. One of the most serious problems in electrocatalytic CO 2 reduction (CO 2 R) is the low solubility of CO 2 in an aqueous electrolyte, which significantly limits the cathodic reaction rate. This paper proposes a facile method of catholyte‐free electrocatalytic CO 2 reduction to avoid the solubility limitation using commercial tin nanoparticles as a cathode catalyst. Interestingly, as the reaction temperature rises from 303 K to 363 K, the partial current density (PCD) of formate improves more than two times with 52.9 mA cm −2 , despite the decrease in CO 2 solubility. Furthermore, a significantly high formate concentration of 41.5 g L −1 is obtained as a one‐path product at 343 K with high PCD (51.7 mA cm −2 ) and high Faradaic efficiency (93.3 %) via continuous operation in a full flow cell at a low cell voltage of 2.2 V.