Synthesis and Photocatalytic Activity of Calcium Antimony Oxide Hydroxide for the Degradation of Dyes in Water

CaSb 2 O 5 (OH) 2 nanocrystals were synthesized via a facile microwave-hydrothermal method. The physicochemical properties of the as-synthesized CaSb 2 O 5 (OH) 2 photocatalyst were characterized by X-ray diffraction, UV−vis diffuse reflectance spectroscopy, transmission electron microscopy, electron spin resonance, and X-ray photoelectron spectroscopy. The photocatalytic activity was evaluated by the decomposition of rhodamine B, methyl orange, and methylene blue in aqueous solution under UV irradiation. For comparison purposes, we have also investigated the activity of TiO 2 (P25, Degussa Co.) under the same condition. The results revealed that the sample had a much higher photocatalytic activity than that of P25. The high activity and long-term stability of CaSb 2 O 5 (OH) 2 were mainly attributed to its stronger oxidative capability and larger specific surface area in comparison with P25. This article presents a detailed analysis of the intermediates produced in the photocatalytic reactions using the liquid chromatography−mass spectrometry technique. The possible photocatalytic reaction pathways as to how CaSb 2 O 5 (OH) 2 nanocrystals degrade organic dyes have also been proposed.