A naturally occurring water‐soluble cobalt‐complex cyanocobalamin (Vitamin B12) has been identified as a new and efficient electrocatalyst for the CO₂‐to‐CO reduction reaction in aqueous solution. Heterogeneous B12‐electrocatalysts prepared by a simple electrochemical immobilization technique on graphene‐oxide (GO)‐modified glassy carbon and carbon paper (CP) electrodes, without any non‐degradable polymer‐binders, showed a highly stable and well‐defined surface‐confined redox peak at E’=−0.138 V vs. RHE with a surface‐excess value, Γ_B12=4.28 nmol cm⁻². This new electrocatalyst exhibits 93 % Faradaic efficiency for CO₂‐to‐CO conversion at an electrolysis potential, −0.882 V vs. RHE (an optimal condition) with a high current density, 29.4 mA cm⁻² and turn‐over‐frequency value, 5.2 s⁻¹, without any surface‐fouling problem, in 0.5 m KHCO₃. In further, it follows an eco‐friendly, sustainable and water‐based approach with the involvement of biodegradable and non‐toxic chemicals/materials like B12, GO and CP.

中文翻译：

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维生素B12（氰基钴胺复合物）固定的氧化石墨烯，可高效进行电催化二氧化碳还原反应。

天然存在的水溶性钴络合物氰钴胺素（维生素B12）已被认为是水溶液中CO ₂到CO还原反应的新型高效电催化剂。通过简单的电化学固定技术在氧化石墨烯（GO）改性的玻璃碳和碳纸（CP）电极上制备的多相B12电催化剂，没有任何不可降解的聚合物粘合剂，表现出高度稳定且定义明确的表面在氧化还原峰Ê “= -0.138 V，相对于RHE与表面过剩值，Γ _B12 = 4.28纳摩尔厘米^-2。这种新型电催化剂对CO ₂表现出93％的法拉第效率电解电位下-CO转换为-0.882 V vs. RHE（最佳条件），具有高电流密度，29.4 mA cm ^-2和转换频率值为5.2 s ^-1，没有任何表面污垢问题是在0.5  m KHCO _3中。此外，它遵循一种生态友好，可持续和水基方法，并涉及可生物降解的无毒化学品/材料，例如B12，GO和CP。