Pt-Substituted polyoxometalate modification on the surface of low-cost TiO2 with highly efficient H2 evolution performance

Abstract

In this study, Pt-substituted polyoxometalate was first modified on the surface of commercially available TiO₂, forming an efficient photocatalyst with high reactivity for hydrogen evolution. During the photocatalytic process, Pt-polyoxometalates not only increase the mobility rate of electrons but also improve the separation efficiency of photoinduced electrons and holes. After photoreduction, the in situ generated Pt⁰ species are anchored on the surface of polyoxometalate anion, which prevents further agglomeration. Then, the in situ formed Pt⁰ species and polyoxometalates synergistically promote the efficiency of photoinduced electron transfer from TiO₂ to the protons adsorbed on the Pt⁰ surface. Although the content of Pt⁰ in the nanocomposite is only 0.6%, the photocatalytic hydrogen production rate reaches 5.6 mmol g⁻¹ h⁻¹ and remains stable at 4.5 mmol g⁻¹ h⁻¹ after the continuous catalytic process. Due to the modification of TiO₂ by Pt-substituted polyoxometalate, this nanocomposite represents a practical model that possesses highly efficient photoelectric conversion performance. The presented work not only extends the family of new TiO₂-polyoxometalate-based materials but also takes a further step toward the practical application of commercial TiO₂ in photocatalytic hydrogen production.