Electrodeposition of Bi nanocomposite with MIL-101 derived carbon as gas diffusion layer for CO2 electroreduction with enhanced formate generation

Herein, a novel and flexible self-supporting gas diffusion electrode (GDE) was fabricated, which including an electrodeposited Bi nanocomposite as a catalyst layer and MIL-101 derived porous carbon in the gas diffusion layer (GDL). Compared with the conventional fabrication of GDE electrodes, the electrodeposition approach can avoid the tedious drop-casting processes of the catalyst layer (CL). The in situ growth mode by electrodeposition can also ensure the firmly interaction between CL and current collector, thus enhancing the stability of the electrode. Meanwhile, the porous carbon derived from MIL-101 which with a high specific area is conducive for the CO₂ enrichment on the electrode, thus facilitate the reaction with high current density. Owe to the special structure, the resultant catalyst showed excellent performance for electrocatalytic CO₂ reduction reaction (CO₂RR) with enhanced formic acid generation. Notably, at -1.37 V (vs. RHE), a large current density of 400 mA cm^-2 and a high formate Faraday efficiency (FE_formate) of 96.5 % were achieved, and the yield of formic acid reached 46.5 mmol cm^-2 h^-1, which is superior to most electrocatalytic catalysts for CO₂RR. In addition, the FE_formate value remained high (>90 %) over a wide voltage window of 800 mV, and the catalyst also maintained stable operation at industrial current density for 70 h. This work provides a new strategy for the design of GDEs with novel structure to achieve high activity and durability for different electrocatalysis.