Ordered Mesoporous Black TiO₂ as Highly Efficient Hydrogen Evolution Photocatalyst

TLDR

Mesoporous TiO₂ has attracted growing interest due to its exceptional properties and broad potential applications. The study reports a facile synthesis of ordered mesoporous black TiO₂ (OMBT) that shows superior photocatalytic hydrogen evolution performance. By employing a thermally stable, high‑surface‑area mesoporous TiO₂ precursor, the authors enable H₂ diffusion, preserve ordered porosity, and suppress anatase‑to‑rutile transformation and crystal growth during 500 °C hydrogenation. The OMBT materials exhibit a surface area of ~124 m² g⁻¹, pore size ~9.6 nm, pore volume 0.24 cm³ g⁻¹, broaden photoresponse into visible and infrared light, and achieve a solar‑driven hydrogen production rate of 136.2 µmol h⁻¹—almost twice that of pristine mesoporous TiO₂.

Abstract

Mesoporous TiO2 has gained increasing interest because of its outstanding properties and promising applications in a wide range of fields. Herein, we report the facile synthesis of ordered mesoporous black TiO2 (OMBT) materials, which exhibit excellent photocatalytic hydrogen evolution performances. In this case, the employment of a thermally stable and high-surface-area mesoporous TiO2 as the hydrogenation precursor is the key for fabricating the OMBT materials, which not only facilitate H2 gas diffusion into TiO2 and interaction with their structures but also maintain the ordered mesoporous structures as well as inhibit the phase transformation (from anatase to rutile) and crystal growth during hydrogenation at 500 °C. The resultant OMBT materials possess a relatively high surface area of ∼124 m(2) g(-1) and a large pore size and pore volume of ∼9.6 nm and 0.24 cm(3) g(-1), respectively. More importantly, the OMBT materials can extend the photoresponse from ultraviolet to visible and infrared light regions and exhibit a high solar-driven hydrogen production rate (136.2 μmol h(-1)), which is almost two times as high as that of pristine mesoporous TiO2 (76.6 μmol h(-1)).