Noble Metal-Free TiO₂-Coated Carbon Nitride Layers for Enhanced Visible Light-Driven Photocatalysis

Composites of g-C₃N₄/TiO₂ were one-step prepared using electron impact with dielectric barrier discharge (DBD) plasma as the electron source. Due to the low operation temperature, TiO₂ by the plasma method shows higher specific surface area and smaller particle size than that prepared via conventional calcination. Most interestingly, electron impact produces more oxygen vacancy on TiO₂, which facilitates the recombination and formation of heterostructure of g-C₃N₄/TiO₂. The composites have higher light absorption capacity and lower charge recombination efficiency. g-C₃N₄/TiO₂ by plasma can produce hydrogen at a rate of 219.9 μmol·g^-1·h^-1 and completely degrade Rhodamine B (20mg·L^-1) in two hours. Its hydrogen production rates were 3 and 1.5 times higher than that by calcination and pure g-C₃N₄, respectively. Electron impact, ozone and oxygen radical also play key roles in plasma preparation. Plasma has unique advantages in metal oxides defect engineering and the preparation of heterostructured composites with prospective applications as photocatalysts for pollutant degradation and water splitting.