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.