Structural dependence of photocatalytic hydrogen production over La/Cr co-doped perovskite compound ATiO3 (A = Ca, Sr and Ba)
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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