Photothermally Driven Efficient CO ₂ Electroreduction Based on a Superhydrophobic Electrode

Electrochemical CO 2 reduction reaction (eCO 2 RR) offers a promising route to produce value-added chemicals and fuels while mitigating carbon emissions. However, challenges of insufficient mass transfer, competitive hydrogen evolution, and sluggish kinetics persist. Thermal activation can improve kinetics, but conventional heating suffers from energy inefficiency and CO 2 solubility degradation. Herein, we report a superhydrophobic triphase photothermal electrode (TPTE) that synergistically integrates localized photothermal heating with interfacial gas transport engineering. This architecture enables precise and energy-efficient heating at the catalyst/electrolyte/gas triphase interface while sustaining high CO 2 availability, overcoming a classical issue of trade-off between temperature and gaseous solubility. Integrating a Au nanoparticle electrocatalyst with a photothermal porous superhydrophobic carbon substrate, TPTE achieves a 260% enhancement in CO partial current density under 400 mW·cm –2 illumination compared to that under ambient conditions while effectively suppressing hydrogen evolution. Mathematical models verify diffusion rate, and interfacial CO 2 concentrations determine eCO 2 RR performance. Under 400 mW·cm –2 illumination, the CO 2 supply rate of TPTE is 50 times higher than that of conventional diphase electrodes. Moreover, the triphase system maintains interfacial CO 2 concentrations near saturation, far exceeding those of diphase systems. This work establishes a generalized interface design strategy for decoupled thermal and mass transport management, offering novel insights into high-performance eCO 2 RR.