Tailoring charge transport in BaBiO3/NaTaO3 heterojunction interface for enhanced photocatalytic and photoelectrochemical H2 generation

• Published in: Journal of photochemistry and photobiology. A, Chemistry. Vol. 391; p. 112363
• Main Authors: Mora-Hernandez, J.M., Huerta-Flores, Ali M., Torres-Martínez, Leticia M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-03-2020
• Subjects: Heterogeneous photocatalysis; Hydrogen production; Photoelectrochemistry; Photoelectrochemistry; Heterogeneous photocatalysis; Hydrogen production
• ISSN: 1010-6030; 1873-2666
• DOI: 10.1016/j.jphotochem.2020.112363

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•BaBiO3/NaTaO3 photocatalyst is reported for the first time to perform the H2 generation.•20 wt.% BaBiO3/NaTaO3 generated 1.4 times more hydrogen than pure NaTaO3.•BaBiO3 addition to NaTaO3 promoted a red-shift enhancing the visible light harvesting.•BaBiO3/NaTaO3 initiates the water-splitting process by the generation of ∙OH radicals.•The formation of heterojunction outstripped the charge recombination issues.
Photoactive perovskites NaTaO3 and BaBiO3 were synthesized by the solid-state method. The resulting compounds were mixed by wet impregnation, adding BaBiO3 (BBO) onto the base material NaTaO3 (NTO) to obtain the compounds X-BBO/NTO (X = 5–30 wt.%). The sample 20-BBO/NTO presented the largest crystallites (135 nm). Since BaBiO3 presents narrower Eg value (≈ 2 eV) than NaTaO3 (≈ 4 eV), the addition of BBO to NTO promoted a better visible light harvesting. This feature can be explained by the formation of a heterojunction, which improves the photocatalytic activity by an abatement of the charge carrier recombination. Photoelectrochemical tests showed an improvement in the charge transfer resistance and enhanced photoelectrocatalytic activity for the 20-BBO/NTO sample, over the other BBO concentrations and bare photocatalysts. An optimal amount of BaBiO3 (20 wt.%) increased the synergy of the n-type heterojunction by an enhancement in the charge transfer processes to perform the photoelectrocatalytic water splitting. 20-BBO/NTO sample showed the highest hydrogen production of 54 μmol g−1, which outstripped 1.4 times the photocatalytic hydrogen generation of the bare NaTaO3 semiconductor.