上海科技大学知识管理系统

Sm2Ti2S2O5 (STSO) was prepared by a flux method using TiO2, TiS2 and Sm2O3 as reactants, and eutectic of LiCl and KCl (LiCl-KCl) or LiCl and CsCl (LiCl-CsCl) as flux. By analyzing X-ray diffraction patterns of the samples synthesized at different temperatures, it was firstly demonstrated that the threshold crystallization temperature of STSO was 520 degrees C, much lower than the value of 650 degrees C that was reported previously as the lowest temperature for synthesizing STSO. Scanning electron microscope images showed that the synthesized STSO particles owned a plate-like morphology. At the same temperature, LiCl-CsCl led to lower plate thickness than LiCl-KCl. The average photocatalytic H-2 production rate showed volcano-like profile to synthesizing temperature, which was likely due to the effect of particle size and crystallinity on activity. Variation of hole sacrificial reagent showed that ascorbic acid produced much higher H-2 evolution activity than Na2S-Na2SO3, triethylamine, triethanolamine and methanol. For the purpose of comparing with the literatures, Na2S-Na2SO3 was employed as sacrificial reagent in the following stability test. It was found that the as-prepared STSO exhibited stable H-2 production over 20 h under visible light (Xe lamp, lambda > 420 nm) irradiation, and having nearly identical characterization results in XPS, XRD and TEM before and after photocatalytic reaction.