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

<p>Electrolyzers combining CO2 reduction (CO2R) 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 –CO2R 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:H2 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 CO2R to less energy demanding, and value?added, oxidative chemistry.</p>