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.

Chemical vapor deposition growth of phase-selective inorganic lead halide perovskite films for sensitive photodetectors

Inorganic lead halide perovskites are attractive optoelectronic materials owing to their relative stability compared to organic cation alternatives.The chemical vapor deposition(CVD) method offers potential for high quality perovskite film growth.The deposition temperature is a critical parameter determining the film quality owing to the melting difference between the precursors.Here,perovskite films were deposited by the CVD method at various temperatures between 500-800℃.The perovskite phase converts from CsPb_(2)Br_(5) to CsPbBr_(3) gradually as the deposition temperature is increased.The grain size of the perovskite films also increases with temperature.The phase transition mechanism was clarified.The photoexcited state dynamics were investigated by spatially and temporally resolved fluorescence measurements.The perovskite film deposited under 750℃ condition is of the CsPbBr_(3) phase,showing low trap-state density and large crystalline grain size.A photodetector based on perovskite films shows high photocurrent and an on/off ratio of ~2.5×10^(4).

A phase-selective,bis-urea organogelator with a curved bis-naphthalene core

A phase-selective,bis-urea organogelator with a curved bis-naphthalene core was synthesized and characterized.This gelator is capable of gelating a variety of hydrocarbons and oils.The resulting gels have been characterized by rheology,SEM,and molecular modelling.The gelator can be applied in the powder form for the recovery of a thin layer of petrol oil spill in water.

Phase engineering of two-dimensional transition metal dichalcogenides

Two-dimensional(2D) transition metal dichalcogenides(TMDs) have gained much attention in virtue of their various atomic configurations and band structures.Apart from those thermodynamically stable phases, plenty of metastable phases exhibit interesting properties. To obtain 2D TMDs with specific phases, it is important to develop phase engineering strategies including phase transition and phaseselective synthesis. Phase transition is a conventional method to transform one phase to another, while phase-selective synthesis means the direct fabrication of the target phases for2D TMDs. In this review, we introduce the structures and stability of 2D TMDs with different phases. Then, we summarize the detailed processes and mechanism of the traditional phase transition strategies. Moreover, in view of the increasing demand of high-phase purity TMDs, we present the advanced phase-selective synthesis strategies. Finally, we underline the challenges and outlooks of phase engineering of 2D TMDs in two aspects-high phase purity and excellent controllability. This review may promote the development of controllable phase engineering for 2D TMDs and even other2D materials toward both fundamental studies and practical applications.