A Precious‐Metal‐Free Hybrid Electrolyzer for Alcohol Oxidation Coupled to CO <sub>2</sub> ‐to‐Syngas Conversion
Mark A. Bajada, Souvik Roy, Julien Warnan, Kaltum Abdiaziz, Andreas Wagner, Maxie M. Roessler, Erwin Reisner
Abstract
Abstract Electrolyzers combining CO 2 reduction (CO 2 R) with organic substrate oxidation can produce fuel and chemical feedstocks with a relatively low energy requirement when compared to systems that source electrons from water oxidation. Here, we report an anodic hybrid assembly based on a (2,2,6,6‐tetramethylpiperidin‐1‐yl)oxyl (TEMPO) electrocatalyst modified with a silatrane‐anchor ( STEMPO ), which is covalently immobilized on a mesoporous indium tin oxide ( meso ITO) scaffold for efficient alcohol oxidation (AlcOx). This molecular anode was subsequently combined with a cathode consisting of a polymeric cobalt phthalocyanine on carbon nanotubes to construct a hybrid, precious‐metal‐free coupled AlcOx–CO 2 R electrolyzer. After three‐hour electrolysis, glycerol is selectively oxidized to glyceraldehyde with a turnover number (TON) of ≈1000 and Faradaic efficiency (FE) of 83 %. The cathode generated a stoichiometric amount of syngas with a CO:H 2 ratio of 1.25±0.25 and an overall cobalt‐based TON of 894 with a FE of 82 %. This prototype device inspires the design and implementation of nonconventional strategies for coupling CO 2 R to less energy demanding, and value‐added, oxidative chemistry.