A two-step synthesis of NaTaO3 microspheres for photocatalytic water splitting

•NaTaO3 microspheres were synthesized via a newly developed two-step processing without using any templates or surfactants.•NaTaO3 microspheres have rough surfaces composed of many tiny particles.•NaTaO3 microspheres show superior photocatalytic activity for water splitting.•The rough surface favors the separation of photogenerated charges and the adsorption of water molecules.

NaTaO3 photocatalyst has been successfully synthesized by a two-step synthesis approach, namely, molten salt in combination with hydrothermal processing at a relatively low temperature. The key concept of the approach is using molten salt to convert Ta2O5 to a soluble Ta-precursor, and the aqueous solution of the obtained Ta-precursor is then transferred as a starting source of Ta to synthesize NaTaO3 by a hydrothermal process. The obtained sample was characterized by powder X-ray diffraction (XRD), inductively coupled plasma emission spectrometry (ICP), field emission scanning electron microscopy (FESEM) and ultraviolet–visible (UV–vis) spectroscopy. A spherical morphology for NaTaO3 has been observed by FESEM. Comparative study on hydrogen production from water splitting under UV-light irradiation evinces that the obtained sample exhibits more than 4 times higher photoactivity than its counterpart prepared by a solid state method. In addition, loading of NiO co-catalyst onto the surface of NaTaO3 improves its efficiency for water splitting.

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