The effect of defect on the photocatalytic and photoelectric performance of BiPO4 has been revealed. The bulk defects of BiPO4 such as bismuth vacancies(VBi), oxygen vacancies(VO) and so on were formed during the ball-milling process. These bulk defects of BiPO4 inhibited the separation of photo-generated charges greatly and thus reduced photocatalytic activity. Most of the bulk defects were repaired and the photocatalytic activity of BiPO4 was also recovered mostly via calcination and reflux. Reflux could repair the bulk defects of BiPO4 much better than calcination. The mechanism of the photocatalytic degradation of pollutants over BiPO4 was not changed by defects, and the main oxidation active species of BiPO4 is photo-generated hole.

At present, composite photocatalysts containing MoS2 as a co-catalyst and a subjective semiconductor material are usually obtained via various complex reduction methods using NH4MoS4 or Na2MoO4 as a precursor. In this work, a simple method was proposed to synthesize MoS2-TiO2 composite photocatalysts via mechanochemistry using MoS2 as a direct precursor. 4.0% MoS2-TiO2 after ball-milling at 300 rpm for 2 h possessed the maximum photocatalytic activity for H2 evolution. The rate of H2 evolution was up to 150.7 μmol h(-1), which was 48.6 times higher than that of pure TiO2. The MoS2-TiO2 composite possesses stable photocatalytic performance for H2 evolution. Photoelectrochemical measurements confirmed the electronic interaction between TiO2 and MoS2. The photo-generated electrons on the conduction band of TiO2 could easily transfer to the MoS2 co-catalyst, which promoted efficient charge separation and improved the photocatalytic performance.

Photo-generated charges of BiPO4 with a phase junction could be separated and transferred quickly, which enhanced the photocatalytic performance.

Enhancement of full-spectrum photocatalytic activity over BiPO4/Bi2WO6 composites, Applied Catalysis B, Environmental http://dx.Highlights 9  BiPO4/Bi2WO6 composite photocatalysts were prepared via ultrasonic-calcination method. 10  BiPO4/Bi2WO6 composites had superior photocatalytic performance under full-spectrum 11 condition. 12  The enhancement mechanism of photocatalytic activity over BiPO4/Bi2WO6 was 13 systematically investigated. 14  *Graphical Abstract 15 2  16 17 3 Abstract: The full-spectrum photocatalytst is of important value for the practical use, which 18 could absorb natural sunlight for photoctalytic degrading organic pollutants. BiPO4/Bi2WO6 19 composite photocatalysts were prepared via ultrasonic-calcination method and had superior 20 photocatalytic performance for degrading different kinds of organic pollutants under simulant 21 sunlight irradiation. The apparent rate constant of 5.0%BiPO4/Bi2WO6 on the degradation of 22 methylene blue (MB) is 0.0305 min -1 , which is about 25.4 and 3.2 times of pure BiPO4 and 23 Bi2WO6 respectively. In the BiPO4/Bi2WO6 composite photocatalysts, the core-hole structure 24 of BiPO4 as core and Bi2WO6 as hole was formed. During the photocatalytic process of 25 BiPO4/Bi2WO6 composites under simulant sunlight irradiation, the photo-generated electrons 26 of BiPO4 would inject to the conduction band of Bi2WO6, and the photo-generated holes on 27 Bi2WO6 could transfer to the valance band of BiPO4, and then an effective charges separation 28 was achieved. The interaction of BiPO4 and Bi2WO6 not only expanded the range of absorption 29 spectrum but also enhanced the separation efficiency of photo-generated charges, and further 30 improved the photocatalytic performance.31

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