Proof-of-concept Study of a New Microflow Electrochemical Cell Design for Gas-Evolving Reactions

This work presents a proof-of-concept demonstration of a new microflow electrochemical cell design for diminishing the side effects of the gas evolved at the electrodes including nonuniform current density distribution and shortened residence time of liquid phase. Gas-permeable material is used to fabricate the microchannel layer of the cell which is configured with an auxiliary vacuum microchannel alongside the reaction microchannel. Electrosynthetic results for two model reactions in a homemade microflow cell utilizing the new design indicated that gas in the reaction channel was partly transferred to the vacuum channel, bringing about the occurrence of many short liquid plugs in the reaction channel as well as reduced gas hold-up and nonuniformity in current density distribution. Thus, side reactions were significantly restrained, yielding superior reaction selectivity: 81% to 91% at 0.1 A for dimethoxylation of furan and 51% to 61% at 5 V for hydrodimerization of adiponitrile. These preliminary results prove the feasibility of the new electrolysis cell design which can be further optimized to perform efficient and selective gas-evolving electrosynthesis in microflow.