The establishment of p-n heterojunction between semiconductors is an effective means to improve the performance of semiconductor photocatalysts. For the first time, we synthesize SnO/BiOBr heterojunction photocatalysts using a one-step hydrothermal method. Systematic material characterizations suggest that the photocatalysts consist of irregular BiOBr nanosheets with the length about 200 nm and width about 150 nm, and SnO nanoparticles are anchored uniformly onto the nanosheets. Most importantly, electrochemical characterizations including transient photocurrent profiles and electrochemical impedance spectra suggest that SnO/BiOBr heterojunctions are created, which facilitates the charge separation and transfer efficiency of photogenerated charge carriers. As such, SnO/BiOBr photocatalysts exhibit remarkable photocatalytic activities in terms of degrading a series of organic pollutants. Radical trapping experiments and electron spin resonance spectra suggest that superoxide radicals (•O) and hydroxyl radicals (•OH) are primary medium species running through the photocatalytic degradation process and enhanced photocatalytic performance.

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Anatase TiO2 with {001} facets is much more active than that with {101} facets, which has been verified via experiments and theoretical calculations. Graphene has garnered much attention since it was initially synthesized, due to its unique properties. In this study, reduced graphene oxide (RGO)/{001} faceted TiO2 composites were fabricated via a solvothermal method. The composites were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectrophotometry, photoluminescence and Raman analysis. The results revealed that the graphene oxide was reduced during the preparation process of the {001} faceted TiO2, and combined with the surface of {001} TiO2. The photocatalytic activities of the composites were evaluated through the degradation of basic violet, under both white light (λ > 390 nm) and visible light (λ = 420 nm) irradiation. The results indicated that the photocatalytic activities of the {001} faceted TiO2 were significantly improved following the incorporation of RGO, particularly under visible light irradiation. Theoretical calculations showed that the band structure of the {001} faceted TiO2 was modified via graphene hybridization, where the separation of photoinduced electron–hole pairs was promoted; thus, the photocatalytic activity was enhanced.

The introduction of carbon (C) into TiO2 may facilitate charge transfer and thus improve its photocatalytic activities. In this paper, C was introduced into N, Zr/TiO2 via ultrasound and calcination using glucose as carbon precursor. The as-prepared C@N, Zr/TiO2 was characterized by SEM, TEM, XRD, UV-Vis DRS, and XPS. The adsorption abilities of the materials were evaluated using two anion dyes [methylene blue (MB) and basic violet (BV)] and two cation dyes [titan yellow (TY) and congo red (CR)] as model pollutants. The photocatalytic activities were investigated through the degradation of Ciprofloxacin (CIP) under simulated sunlight irradiation. The results revealed that the appropriate introduction of carbon may improve the adsorption abilities and the photocatalytic activities of non-carbonaceous materials. Furthermore, several samples exhibited selective adsorption abilities for cation dyes, which suggested the potential application of the as-prepared materials for the selective removal of co-existing pollutants.