Present and Future of Phase-Selectively Disordered Blue TiO₂ for Energy and Society Sustainability

Titanium dioxide (TiO₂) has garnered attention for its promising photocatalytic activity, energy storage capability, low cost, high chemical stability, and nontoxicity. However, conventional TiO₂ has low energy harvesting efficiency and charge separation ability, though the recently developed black TiO₂ formed under high temperature or pressure has achieved elevated performance. The phase-selectively ordered/disordered blue TiO₂ (BTO), which has visible-light absorption and efficient exciton disassociation, can be formed under normal pressure and temperature (NPT) conditions. This perspective article first discusses TiO₂ materials development milestones and insights of the BTO structure and construction mechanism. Then, current applications of BTO and potential extensions are summarized and suggested, respectively, including hydrogen (H₂) production, carbon dioxide (CO₂) and nitrogen (N₂) reduction, pollutant degradation, microbial disinfection, and energy storage. Last, future research prospects are proposed for BTO to advance energy and environmental sustainability by exploiting different strategies and aspects. The unique NPT-synthesized BTO can offer more societally beneficial applications if its potential is fully explored by the research community.