•Dark orange montmorillonite/g-C3N4 composites had been successfully synthesized via a calcination method.•The montmorillonite/g-C3N4 composites exhibited improved photocatalytic performance in the degradation of methylene blue.•The improved photocatalytic performance is due to an enhanced visible light absorbance and good adsorptive capacity to dye.•The montmorillonite/g-C3N4 composites could be used for the detection of trace amounts Cu2+.Dark orange montmorillonite/g-C3N4 composites were prepared through a conventional calcination route. The obtained samples were analyzed by XRD, TEM, TG, XPS, FT-IR, DRS, Photocurrent-time and PL measurements. The photocatalytic performance of montmorillonite/g-C3N4 composites was assessed by the methylene blue (MB) degradation. Compared to pure g-C3N4, the obtained photocatalysts displayed outstanding photocatalytic activity. The improved photocatalytic activity was ascribed to the improved absorbance in the visible light range and favorable adsorptive capacity to MB dye. The electron spin resonance (ESR) analysis and trapping experiment showed that •O2− and h+ played a major role in the decomposition of MB. In addition, it was found that montmorillonite/g-C3N4 (0.5) composite had a new property, which showed that it can be applied as a sensor in the photoelectrochemical detection of trace amount of Cu2+.Dark orange montmorillonite/g-C3N4 composites were synthesized through a conventional calcination method. The composites displayed superior photocatalytic activity under visible light irradiation. The improved photocatalytic performance is attributed to the enhanced visible light absorbance and good adsorptive capacity to dye. It was found that •O2− and h+ played a major role in photocatalytic degradation process. Further studies showed that the composite could also be used for the detection of trace amounts Cu2+. It is a new but promising candidate for the application in the water environment.Download high-res image (256KB)Download full-size image

A novel ternary composite photocatalyst (g-C3N4/BiOI/BiOBr) was prepared via a facile solvothermal method. The samples were characterized by powder X-ray diffraction, transmission electron microscopy, UV-visible diffuse reflection spectrometry, X-ray photoelectron spectrometry and photoluminescence measurements. Under irradiation with visible light, the g-C3N4/BiOI/BiOBr photocatalyst showed a higher photocatalytic activity than pure g-C3N4 and BiOI/BiOBr for the degradation of methylene blue. Among the hybrid photocatalysts, 3% g-C3N4/BiOI/BiOBr showed the highest photocatalytic activity for the degradation of MB. These results suggest that the heterostructure combination of g-C3N4, BiOI and BiOBr provides a synergistic effect through an efficient charge transfer process.

•Novel g-C3N4/Bi2O3 composites were synthesized by a mixing-calcination method.•The g-C3N4/Bi2O3 composites show high visible-light photocatalytic performance.•The enhanced photocatalytic activity is mainly attributed to effective separation of electron and hole.Novel g-C3N4 modified Bi2O3 (g-C3N4/Bi2O3) composites were synthesized by a mixing-calcination method. The samples were characterized by thermogravimetry (TG), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), UV–vis diffuse reflection spectroscopy (DRS), photoluminescence (PL) and photocurrent-time measurement (PT). The photocatalytic activity of the composites was evaluated by degradation of Rhodamine B (RHB) and 4-chlorophenol (4-CP) under visible light irradiation (>400 nm). The results indicated that the g-C3N4/Bi2O3 composites showed higher photocatalytic activity than that of Bi2O3 and g-C3N4. The enhanced photocatalytic activity of the g-C3N4/Bi2O3 composites could be attributed to the suitable band positions between g-C3N4 and Bi2O3. This leads to a low recombination between the photogenerated electron–hole pairs. The proposed mechanism for the enhanced visible-light photocatalytic activity of g-C3N4/Bi2O3 composites was proven by PL and PT analysis.

•A novel C/g-C3N4 composite photocatalyst has been synthesized.•Carbon-doping enhanced g-C3N4 adsorptivity, visible-light absorption and photocurrent response.•The synergetic effect contributed to the improved photocatalytic activity of the C/g-C3N4 composites.Novel visible-light-active carbon-doped graphitic carbon nitride composites (C/g-C3N4) were prepared by hydrothermal treatment of the mixture of g-C3N4 and glucose solution. The products were characterized by X-ray diffraction, transmission electron microscopy (XRD), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflection spectroscopy (UV–vis), and photocurrent–time measurement (PT). Compared to g-C3N4, the C/g-C3N4 showed enhanced visible-light absorption, adsorptivity and improved photocurrent response. C/g-C3N4 composites also showed enhanced performance for Methylene Blue (MB) photodegradation. The enhanced activity of the C/g-C3N4 composites is attributed to the synergistic effect between the doped carbon and g-C3N4.

Novel WO3/g-C3N4 composite photocatalysts were prepared by a calcination process with different mass contents of WO3. The photocatalysts were characterized by thermogravimetric analysis (TG), powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS), high-resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflection spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and electrochemical impedance spectroscopy (EIS). The photocatalytic activity of the photocatalysts was evaluated by degradation of methylene blue (MB) dye and 4-chlorophenol (4-CP) under visible light. The results indicated that the WO3/g-C3N4 composite photocatalysts showed higher photocatalytic activity than both the pure WO3 and pure g-C3N4. The optimum photocatalytic activity of WO3/g-C3N4 at a WO3 mass content of 9.7% under visible light irradiation was up to 4.2 times and 2.9 times as high as that of the pure WO3 and pure g-C3N4, respectively. The remarkably increased performance of WO3/g-C3N4 was mainly attributed to the synergistic effect between the interface of WO3 and g-C3N4, including enhanced optical absorption in the visible region, enlarged specific surface areas and the suitable band positions of WO3/g-C3N4 composites.

Novel WO3/g-C3N4 composite photocatalysts were prepared by a calcination process with different mass contents of WO3. The photocatalysts were characterized by thermogravimetric analysis (TG), powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS), high-resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflection spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and electrochemical impedance spectroscopy (EIS). The photocatalytic activity of the photocatalysts was evaluated by degradation of methylene blue (MB) dye and 4-chlorophenol (4-CP) under visible light. The results indicated that the WO3/g-C3N4 composite photocatalysts showed higher photocatalytic activity than both the pure WO3 and pure g-C3N4. The optimum photocatalytic activity of WO3/g-C3N4 at a WO3 mass content of 9.7% under visible light irradiation was up to 4.2 times and 2.9 times as high as that of the pure WO3 and pure g-C3N4, respectively. The remarkably increased performance of WO3/g-C3N4 was mainly attributed to the synergistic effect between the interface of WO3 and g-C3N4, including enhanced optical absorption in the visible region, enlarged specific surface areas and the suitable band positions of WO3/g-C3N4 composites.