Defect density modulation of La2TiO5: An effective method to suppress electron-hole recombination and improve photocatalytic nitrogen fixation.

Highly active and efficient photocatalysts are crucial for the exploration of ammonia synthesis because of the serious problem of energy deficiency. La2TiO5 (LTO) perovskite materials have great advantages in the field of photocatalytic nitrogen fixation because of the broadly diversified properties. The rational design of surface defect is a valid method to modulate photoinduced charge traps and create defect energy levels, especially it is an effective way to suppress the photoinduced charge recombination. Herein, LTO was obtained by a simple sol-gel method and was further reduced by NaBH4 to introduce oxygen defect on its surface. UV-vis spectra proved that the surface defects could reduce the band gap value of samples, which is beneficial for improving photocatalytic nitrogen fixation activity. For the best photocatalytic samples with good cycle stability, the nitrogen fixation rate is 158.13 μmol·g-1·h-1. The mechanism of photocatalytic nitrogen fixation was proposed by the PL, XPS, and PEC results, which provided possibilities for exploring more promising perovskite catalysts in the field of nitrogen fixation.