Preparation of g-C₃N₄/Ta₂O₅ Composites with Enhanced Visible-Light Photocatalytic Activity

g-C₃N₄/Ta₂O₅ composites have been synthesized by a facile route in which mixtures of Ta₂O₅ and urea are heated at various temperatures of 450°C, 500°C, and 550°C. The obtained materials (denoted as CN/TaO-T, where T is the heating temperature) were characterized using x-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, infrared spectroscopy, diffuse-reflectance ultraviolet–visible (UV–Vis) spectroscopy, thermogravimetric analysis, and x-ray photoelectron spectroscopy. The results show that the as-prepared composites are in orthorhombic Ta₂O₅ phase coated by g-C₃N₄. The photocatalytic activity of the composites was evaluated by photodegradation of methylene blue under visible light. Among the three materials, CN/TaO-500 exhibited the highest photocatalytic activity. The improved photocatalytic activity of the g-C₃N₄/Ta₂O₅ composites is attributed to the presence of g-C₃N₄ in the materials.