Thermal-driven Z-scheme spinel CuAl₂O₄-decorated TiO₂(B) heterojunction for accelerated charge transfer and enhanced...

Harnessing solar energy for hydrogen (H₂) generation represents a sustainable route toward carbon-neutral energy conversion. However, its efficiency is often hindered by sluggish charge transport and severe carrier recombination. In this work, a thermally driven Z-scheme heterojunction composed of spinel Copper aluminium oxide (CuAl₂O₄) and monoclinic titanium dioxide (TiO₂(B)) is developed to overcome these limitations. CuAl₂O₄, with its suitable band alignment and excellent redox stability facilitates rapid interfacial charge transfer. The well-integrated CuAl₂O₄/TiO₂(B) interface establishes an internal electric field that drives directional charge migration, while thermal excitation further enhances carrier mobility and accelerates surface reaction kinetics. This synergistic photothermal coupling substantially amplifies the H₂ evolution activity, delivering an impressive H₂ production rate of 2687 µmol g^-1 h^-1 under natural sunlight and heat-assisted conditions, along with outstanding durability. The results demonstrate that integrating the robust spinel CuAl₂O₄ with TiO₂(B) via a thermally assisted Z-scheme heterojunction effectively preserves strong redox potentials while minimizing recombination losses, highlighting the potential of this strategy for the rational design of thermally enhanced heterojunction photocatalysts for efficient solar-to-hydrogen conversion.