Wenjia Yang,Wen Cui,Lin Yang,Guo Zhang,Xiaofang Li,Yu Shen,Fan Dong,Yanjuan Sun
Considering that the structural differences could dictate the photocatalytic efficiency, the cubic SrTiO 3 (STO) and tetragonal CaTiO 3 (CTO) were developed to illustrate the structure–activity relationship. The STO with cubic structure demonstrates much higher photocatalytic toluene removal efficiency ( ca. 80.0%) than that of CTO ( ca. 20.0%), which can be ascribed to boosted formation of reactive oxygen species (ROS), increased selectivity of intermediates, and promoted ring-opening and mineralization rate. Combining theoretical simulation and experimental characterization, the results reveal that the O 2 and H 2 O molecules tend to be adsorbed on the cubic STO, which boosts the formation of ROS. Also, highly selective formation of intermediate (benzoic acid) has been realized to accelerate ring-open and mineralization process as evidenced by the smooth conversion of STO as indicated by Gibbs free energy. This work provides new perspectives on the understanding of relationship between intrinsic structure and photocatalytic performance.
Oxides with the ABO 3 chemical formula play a crucial role in studying photostriction in inorganic materials. In this study, the photostrictive behavior of ilmenite-type ceramics ATiO 3 (where A = Mg, Fe, Co, Ni, and Mn) was investigated under visible light irradiation. Among the ceramics investigated, CoTiO 3 showed the highest photostriction of approximately 0.1 % under 405, 520, and 650 nm light irradiation. The photostrictive response decreased successively in FeTiO 3 , MnTiO 3 , NiTiO 3 , and MgTiO 3 . Temperature and thermal expansion tests revealed that the deformation of the ceramics caused by the photothermal effect accounted for approximately half of their photostriction. Raman and charge transfer analyses indicated that the photostriction of the ceramics depended significantly on their crystal structure. Thus, the ceramics exhibited distinct photostrictive performances. This study highlights the connection between the crystal structure and photostrictive performance of ilmenite-type ceramics, providing valuable insights into the underlying mechanism of photostriction in inorganic materials.
The crystal structure of a photocatalyst generally plays a pivotal role in its electronic structure and catalytic properties . In this work, we synthesized a series of La/Cr co-doped perovskite compounds ATiO 3 (M = Ca, Sr and Ba) via a hydrothermal method . Their optical properties and photocatalytic activities were systematically explored from the viewpoint of their dependence on structural variations, i.e. impact of bond length and bond angles. Our results show that although La/Cr co-doping helps to improve the visible light absorption and photocatalytic activity of these wide band gap semiconductors , their light absorbance and catalytic performance are strongly governed by the Ti O bond length and Ti O Ti bond angle. A long Ti O bond and deviation of Ti O Ti bond angle away from 180° deteriorate the visible light absorption and photocatalytic activity. The best photocatalytic activity belongs to Sr 0.9 La 0.1 Ti 0.9 Cr 0.1 O 3 with an average hydrogen production rate ∼2.88 μmol/h under visible light illumination (λ ≥ 400 nm), corresponding to apparent quantum efficiency ∼ 0.07%. This study highlights an effective way in tailoring the light absorption and photocatalytic properties of perovskite compounds by modifying cations in the A site.
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