Defect-Induced Blue and Black TiO2: Inspiring Next Generation Photocatalysts for Solar Hydrogen Production-new

Abstract

This is a paper tobe published Generating hydrogen via photocatalysis using artificial or natural light remains a significant challenge due to insufficient energy conversion in the visible-light spectrum. Recent efforts have focused on synthesizing defect-enriched photocatalysts, with titania (TiO₂) being one of the most extensively studied and modified materials. This study employs both physical and chemical methods to fine-tune intrinsic defects, such as trapped electrons, oxygen vacancies, and/or Ti³⁺ centers, at the surface, subsurface, or within the bulk crystal lattice. We report the synthesis of blue titania, achieved through a single-step hydrogen reduction process at 20 bar pressure and 450°C using commercial white titania, which resulted in a 2.6-fold enhancement in solar hydrogen evolution. This performance was compared with chemically reduced, defect-enriched, colored crystalline TiO₂, prepared under ambient conditions using NaBH₄ as a reductant in either a hydrogen or argon atmosphere.