Laser assisted chemical vapor deposition of nanostructured NaTaO3 and SrTiO3 thin films for efficient photocatalytic hydrogen evolution

•NaTaO3 and SrTiO3 nanostructured thin films were successfully prepared by laser assisted CVD.•NaTaO3 and SrTiO3 thin films catalyzed efficiently hydrogen evolution under UV light.•Best catalytic activity was obtained by NaTaO3 with orthorhombic crystal structure.•Effect of the crystal structure and morphology on the catalytic activity of thin films is discussed.

In this work, we report the preparation of nanostructured NaTaO3 and SrTiO3 thin films on stainless steel substrates by laser assisted chemical vapor deposition (LCVD) and their application as photocatalysts for hydrogen evolution under UV light. The effect of the deposition conditions on the compositions and microstructures of the materials is discussed, and an integral study of the influence of the structural, morphological, optical and photoelectrochemical properties of the films on their catalytic activities for hydrogen production is presented through X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL) and electrochemical impedance spectroscopy (EIS) analyses. The LCVD process allows for the growth of films with attractive microstructures for photocatalytic applications, leading to a roof-like morphology in the case of orthorhombic NaTaO3 and a cauliflower-like morphology for cubic SrTiO3, which promote an enhanced charge separation and transference process and a higher photocatalytic efficiency compared to the photocatalysts prepared as powders. Orthorhombic NaTaO3 exhibits a hydrogen evolution rate of 5672 μmol g−1 h−1, and SrTiO3 generates only 494 μmol g−1 h−1, which are significantly higher than the activities of the materials prepared as powders. This improvement is attributed to the microstructure of the films prepared by LCVD and their superior optical, structural and photoelectrochemical properties. The results of the evaluation of the catalytic activity of the films prepared in this work by LCVD demonstrate the attainment of stable photocatalysts with a competitive performance compared to similar materials prepared by alternative methods.

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