A Precious-metal-free Hybrid Electrolyzer for Alcohol Oxidation Coupled to CO2-to-syngas Conversion.

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 (AlcO x ). 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 AlcO x -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% and 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.