Coupled electrochemical system (CES) for electroreduction of CO₂ and simultaneous degradation of organic pollutants is a promising CO₂ conversion method. However, its performance is severely restrained by insufficient reactants and low electroactive surface areas on the cathode material. Here, a series of novel Sn-based carbon nanotubes (CNTs)/carbon black hybrid gas diffusion electrodes (CNTx/ESGDEs) were fabricated and used as cathodes to enhance the performance of the CES with methyl orange (MO) as a target pollutant. The results show that at an appropriate content of CNTs, the CNTx/ESGDEs offered increased total pore area, porosity, electroactive surface area, and decreased charge transfer resistances. The current density, Faraday efficiency, formic acid production rate, MO removal efficiency, and COD removal efficiency were improved by 140%, 92%, 404%, 76%, and 131%, respectively, at 40 wt% CNTs probably due to enhancement in the electroactive surface area as well as reactant transfer. This study benefits the large-scale applications of CES.

用于电化学还原CO ₂和同时降解有机污染物的耦合电化学系统（CES）是一种很有前途的CO ₂转换方法。然而，其性能受到阴极材料上反应物不足和低电活性表面积的严重限制。在这里，制造了一系列新型的Sn基碳纳米管（CNTs）/炭黑混合气体扩散电极（CNTx / ESGDEs），并用作阴极以增强以甲基橙（MO）为目标污染物的CES的性能。结果表明，在适当的CNT含量下，CNTx / ESGDE可以提供增加的总孔面积，孔隙率，电活性表面积和降低的电荷转移阻力。电流密度，法拉第效率，甲酸生产率，MO去除效率和COD去除效率分别提高了140％，92％，404％，76％和131％。CNT含量为40 wt％可能是由于电活性表面积的增加以及反应物的转移。这项研究有益于CES的大规模应用。