摘要
Nitrogen-doped Ta 2 O 5 (N-Ta 2 O 5 ) powders were fabricated by nitridation of Ta 2 O 5 in NH 3 for 1 h at 600–700 °C. The concentration of nitrogen doping increased as the nitridation temperature increased, and a small amount of Ta 3 N 5 appeared when nitridized at 700 °C. Pure Ta 3 N 5 was obtained by nitridation at 800 °C for 6 h. They were characterized by X-ray diffraction, Raman spectroscopy, X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, UV–vis spectrometry, and photoluminescence spectroscopy. It is concluded that in the N-Ta 2 O 5 samples nitrogen ions have substituted for oxygen ions, creating some oxygen vacancies and extra energy levels within the band gap. Further, Ta 3 N 5 prefers to form on the surface and acts as the recombination center for electrons and holes. Among all samples, nitridation at 650 °C resulted in the best photocatalytic hydrogen production efficiency that can be explained by more nitrogen doping and no formation of Ta 3 N 5 .