Preparation of two-dimensional mesoporous Ta3N5 by utilizing a biological template for enhanced photocatalytic hydrogen production

The design and development of efficient nitride photocatalysts have attracted much attention. Herein, two-dimensional mesoporous Ta3N5 is successfully synthesized through a simple sol-gel process with filter paper as a biological template and a combination of vacuum nitriding reactions. The prepared Ta3N5 shows a wide light response range up to the near infrared (NIR) region due to the nitrogen vacancies generated from substitution of N3- for O2- ions during vacuum nitridation. Significantly, such a narrow bandgap (similar to 1.99 eV) still satisfies the redox potential of water splitting in thermodynamics. The experimental results show that the Ta3N5 photocatalyst exhibits an enhanced hydrogen production rate of 34.6 mu mol h(-1) g(-1), which is 3.9 and 2.1 times higher than that of Ta2O5 and partial nitridation of Ta2O5 (N-Ta2O5), respectively. This enhanced photocatalytic performance could be attributed to the high specific surface area to provide reactive active sites, substitution of N3- for O2- ions to optimize the band structure, and special two-dimensional mesoporous structure to shorten the charge transfer distance. This work provides a new perspective for the preparation of two-dimensional nitride materials by a biological template method combining vacuum nitriding with enhanced photocatalytic performance.