2D/1D graphitic carbon nitride/titanate nanotubes heterostructure for efficient photocatalysis of sulfamethazine under solar light: Catalytic 'hot spots' at the rutile-anatase-titanate interfaces

摘要

2D/1D graphitic carbon nitride hybridized with titanate nanotubes (g-C3N4/TNTs) was prepared through a hydrothermal reaction-calcination method. The photocatalyst exhibited high degradation efficiency for sulfamethazine (SMT) through photocatalysis under simulated solar light. The optimized material was composed of anatase, rutile, titanate and g-C3N4 crystalline phases. In situ transformation of titanate to anatase and rutile with specific content proportion (similar to 80:20, P25-type composition) leaded to formation of nanoscale "hot spots" at rutile-anatase-titanate interfaces, and then subsequent charge transfer occurred. Large specific surface area of TNTs as skeleton resulted in high-efficient interface reaction, while heterojunction with g-C3N4 further extended the adsorption to visible light region and retarded electron-hole pairs recombination. Density functional theory (DFT) calculation indicated the SMT sites with high Fukui nucleophilic (f) index prefered to be attacked by radacils. Reduced toxicity of SMT degradation intermediates, good reusability and stability of g-C3N4/TNTs all suggested the great application potential in practical water treatment area.