Photophysical and enhanced daylight photocatalytic properties of N-doped TiO2/g-C3N4 composites Original Research Article

N-doped TiO2/C3N4 composite samples were synthesized by heating the mixture of the hydrolysis product of TiCl4 and C3N4 at different weight ratios. The samples were characterized by X-ray diffraction (XRD), Raman spectrum, UV–vis absorption spectrum, photoluminescence spectrum, X-ray photon electron spectrum (XPS) and surface photovoltage spectrum (SPS). The XRD and Raman results indicate that the introduction of C3N4 could inhibit the formation of rutile TiO2. The composite samples show slight visible light absorption due to the introduction of C3N4. The XPS result reveals that some amount of nitrogen is doped into TiO2, and C3N4 exists in the composite sample. The intensities of the SPS signal in the composite samples decrease with the rise in the amount of C3N4 in the samples. The photocatalytic activity was evaluated from the Rhodamine B (RhB) degradation under fluorescence light irradiation. The composite samples show significantly enhanced photocatalytic activities and the RhB self-sensitized photodegradation in this system was observed by measuring the photocurrent in the dye sensitized solar cell using the composite as the working electrode.