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

Abstract

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.

MXene-Derived 3D Defect-Rich TiO2@Reduced Graphene Oxide Aerogel with Ultrafast Carrier Separation for Photo-Assisted Uranium Extraction: A Combined Batch, X-ray Absorption Spectroscopy, and Density Functional Theory Calculations

“…As disclosed by Figure S6, the introduction of O v can not only effectively extend the light absorption wavelength of TiO 2 but also significantly enhance the utilization of near-infrared light. Based on the Tauc/Davis–Mott model, the band gaps ( E g ) of the perfect TiO 2 and TiO 2 (M) were 2.97 and 2.88 eV, respectively, revealing that defect engineering (O v ) is a feasible route to realize band adjustment (Figure a) . As indicated by UPS spectra, the valence band (VB) edge positions of the perfect TiO 2 and TiO 2 (M) were calculated to be 6.46 and 6.09 eV versus vacuum level, referring to 1.96 and 1.59 eV versus RHE (Figure b,c).…”

“…The oxygen defect structure inspired and TiO 2 (M) were 2.97 and 2.88 eV, respectively, revealing that defect engineering (O v ) is a feasible route to realize band adjustment (Figure 3a). 33 As indicated by UPS spectra, the valence band (VB) edge positions of the perfect TiO 2 and TiO 2 (M) were calculated to be 6.46 and 6.09 eV versus vacuum level, referring to 1.96 and 1.59 eV versus RHE (Figure 3b,c). Considering the E g value, the conduction band (CB) edge positions of the perfect TiO 2 and TiO 2 (M) were calculated as −1.01 and −1.29 eV versus RHE, respectively.…”

“…However, most of the photocatalysts for uranium extraction suffer from weak long-wavelength light absorption and low uranium absorption capacity . Various strategies have been proposed to optimize the photocatalyst for uranium extraction, including adjusting the energy band structure or introducing adsorption sites on the photocatalyst. ,− An effective method for tailoring the energy band structure originates from introducing impurity energy states into the band gap of photocatalysts, which can be achieved by introducing vacancies. , For example, our previous work demonstrated that efficient uranium extraction could be achieved by defective WO 3– x with a suitable band structure . Apart from introducing vacancies, the introduction of adsorption sites for uranium extraction could be realized by constructing a typical semiconductor-adsorbent heterojunction. , Previous literature reports that graphene aerogel (GA) is an ideal scaffold for encapsulating nanomaterials such as ZnO, Fe 3 O 4 , and TiO 2 , − which can synergistically enhance the performance of photocatalytic extraction of heavy metal ions from aqueous solutions. − In addition, the GA has excellent electrical conductivity and unique three-dimensional (3D) mesoporous channels, which can promote electron transfer in the photocatalytic process .…”

Pseudo-capacitive and kinetic enhancement of metal oxides and pillared graphite composite for stabilizing battery anodes

“…The common metal oxides, tin dioxide (SnO 2 ) and titanium dioxide (TiO 2 ), have been recognized as encouraging and promising LIB anode candidates due to their various advantages 6 – 8 . Initially, SnO 2 drew immense attention mainly due to its higher theoretical lithium-ion (Li + ) storage capacity (1494 mAh g −1 , Li 4.4 Sn) relative to graphite (372 mAh g −1 , LiC 6 ), while being inexpensive and naturally abundant 9 .…”

“…The PGN is introduced to chemically anchor SnO 2 [O]rTiO 2 while acting as a buffer membrane to cushion and prevent the pulverization of SnO 2 [O]rTiO 2 . In order to realize chemical bonding in SnO 2 [O]rTiO 2, we produce a hydroxyl-rich (-OH) surface on TiO 2 by breaking the Ti-oxygen bond, resulting in a reduced TiO 2 (rTiO 2 ) 8 , 21 – 25 . To effectively tackle volume change and pulverization concerns, we tried to adjust and achieve the proper ratio of SnO 2 (~ 3–4 nm) and TiO 2 (~ 5 nm).…”