Boosting photocatalytic hydrogen evolution via interfacial photothermal evaporation on a CdS/CoFe₂O₄ p-n heterojunction

Photocatalytic water splitting emerges as a promising technology for transforming solar energy into hydrogen fuel. Nevertheless, challenges such as inadequate light absorption, substantial heat loss, and sluggish mass-energy transfer in conventional solid-liquid-gas triphase reactions often hinder the improvement of energy conversion efficiency. Here, a photothermally driven gas-solid biphase system is introduced to enhance solar energy utilization. Regarding photocatalyst design, a CdS/CoFe₂O₄ (CCF) p-n heterojunction photocatalyst is fabricated by the calcination method, which facilitates consistent spatial transmission and efficient separation of photogenerated carriers. System construction involves utilizing annealed melamine sponge (AMS) as a photothermal substrate, transforming the solid-liquid-gas triphase system into a more efficient gas-solid biphase configuration. This change improves the overall reaction temperature and significantly transforms the mass transfer dynamics at the catalytic interface. The optimized CCF/AMS gas-solid biphase system demonstrates a remarkable hydrogen evolution rate of 254.1 μmol/h, representing a significant leap forward compared to traditional triphase system. This study offers valuable insights into improving the efficiency of photocatalytic water splitting through innovative material design and novel reaction system construction.