Electrosynthesized Metal/Polymer Hybrid: Unlocking Selective Formate Production via CO2 Electroreduction

Carbon dioxide reduction via electrochemical means offers a sustainable pathway to mitigate CO₂ emissions and synthesize value-added chemicals. Here, we report the synthesis and performance of a metal/polymer-carbon paper (Cu_xO_y/PoPD/CFP) electrode prepared via a simple two-step in situ electrodeposition method for the electrochemical CO₂ reduction reaction (CO₂ER). Unlike most reported catalysts that yield multiple liquid products and complicate downstream separation processes, Cu_xO_y/PoPD/CFP selectively produces formate as the sole liquid product across all of the test potentials. The amine-rich and porous PoPD matrix synergistically enhanced CO₂ capture, provided a conductive scaffold for efficient electron transfer, and facilitated intimate interfacial contact with copper oxides, enabling improved catalytic performance. The catalyst demonstrated an onset potential of ∼−0.27 V (vs RHE) and achieved a faradaic efficiency of 72.6% for formate with a current density of 6.70 mA/cm² at −0.80 V (vs RHE). Studies showcased an electrochemically active surface area (ECSA) of 16.625 cm² and a roughness factor of 8.31. The long-duration electrolysis experiment demonstrated stable performance for an extended period, maintaining continuous electrolysis for up to 9.5 h without significant fluctuations or degradation in activity.