Promotional effect of rare earth (Er, Pr, Nd, Gd and Sm) metals on the photocatalytic H2O splitting activity of Ni–Al doped TiO2 catalysts for H2 production

Abstract

The pursuit of efficient and cost-effective photocatalysts for hydrogen (H₂) evolution remains a crucial challenge in the development of sustainable energy technologies. In this study, rare earth metal (Er, Pr, Nd, Gd and Sm) doped Ni–Al modified TiO₂ catalysts were successfully synthesized via a mechanical mixing method. The structural, morphological, and optical properties of the as-prepared catalysts were systematically characterized. Photocatalytic H₂ evolution tests under visible light irradiation were conducted to evaluate the performance of the Ni–RE–Al/TiO₂ (RE = Er, Pr, Nd, Gd and Sm) catalysts. Among them, the Ni–Gd–Al/TiO₂ catalyst exhibited superior hydrogen evolution activity, achieving a yield of 1503.4 μmol g⁻¹ h⁻¹, compared with other RE doped catalysts. The enhanced H₂ production was attributed to the synergistic interaction between Ni–RE–Al and TiO₂, which altered the electronic structure and enhanced light absorption thereby broadening the photocatalytic activity spectrum. This work contributes to the development of low-cost, environmentally friendly and high-performance photocatalysts for renewable hydrogen production for clean energy technologies.