Electrochemical Conversion of CO₂ to CO into a Microchannel Reactor System in the Case of Aqueous Electrolyte

Zhang, Fanghua; Jin, Zhichao; Chen, Chengzhen; Tang, Yanling; Mahyoub, Samah A.; Yan, Shenglin; Cheng, Zhenmin

Electrochemical Conversion of CO₂ to CO into a Microchannel Reactor System in the Case of Aqueous Electrolyte

2020

A microchannel electrochemical reactor system was designed to facilitate the reduction of CO₂ to CO, which is composed of a premixing section in the upstream consisting of a circular microchannel for the presaturation of CO₂ in the electrolyte and a reacting section in the downstream consisting of an annular microchannel containing a Ag rod as the catalyst. Such a combined structure exhibited an ultrahigh CO faradaic efficiency of 95.3% due to the efficient mass transfer under Taylor flow. It is interesting to find that CO₂ conversion was increased from 0.94 to 3.66% when the length of the microchannel was increased by connection in series due to the prolonged contacting time between CO₂ and the electrocatalyst. Furthermore, “scale-up” experiments demonstrated that the faradaic efficiency for CO could keep all above 95.0% at a current density of 7.5 mA cm² when the microchannel number was increased in parallel, revealing that the microchannel electrochemical reactor is efficient to conduct the electroreduction of CO₂.

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