Selective\nZero-Gap CO<sub>2</sub> Reduction in Acid

The electrochemical CO<sub>2</sub> reduction reaction\n(CO<sub>2</sub>RR) is a promising method of converting CO<sub>2</sub> into valuable\nchemicals and fuels, thereby contributing to carbon neutrality. This\nstudy explores the CO<sub>2</sub>RR under acidic conditions using\na zero-gap electrolyzer, which minimizes ohmic losses by optimizing\nthe electrode proximity. We assessed the performance of the CO<sub>2</sub>RR using a Ni single-atom catalyst, a porous diaphragm, and\nvarious ion-exchange membranes. Our findings show that the porous\ndiaphragm enhances the CO Faraday efficiency (FE) and prevents salt\nformation, which are crucial for maintaining high selectivity and\nsystem durability. Comparative analyses demonstrate that, while traditional\nion-exchange membranes can be faced with considerable salt buildup\nand/or reduced CO FE, the implementation of a zero-gap electrolyzer\nwith a porous diaphragm offers a robust solution, enabling higher\nefficiency and stability, even at increased current densities. These\ndevelopments can help optimize CO<sub>2</sub> electrolyzer technologies\nand enhance their operational and economic viability.