A porous carbon membrane with abundant intrinsic carbon defects as an integrated gas-diffusion electrode for CO₂ electroreduction

A highly defective, self-supported porous carbon membrane (HDPCM) electrode is developed via CO2-assisted thermal etching of carbonized wood. The as-fabricated HDPCM is heteroatom-free and features abundant intrinsic carbon defects with enhanced CO2 adsorption and activation capability, and thus exhibits high efficiency for electrocatalytic CO2-to-CO conversion with a faradaic efficiency (FECO) of 81.1% and a partial current density (j(CO)) of -3.88 mA cm(-2) at -0.66 V versus reversible hydrogen electrode (RHE). Notably, after hydrophobic treatment, the HDPCM can be directly used as an integrated gas-diffusion electrode (GDE) in the flow cell, further delivering a much enhanced and relatively stable j(CO) (-50 mA cm(-2) at -0.76 V vs. RHE). This work not only contributes to an effective strategy for creating intrinsic defects on carbon-based electrocatalysts but also provides a new insight into the development of integrated metal-free carbon-based GDEs for large-scale CO2 electroreduction.