Robust route to photocatalytic nitrogen fixation mediated by capitalizing on defect-tailored InVO4 nanosheets

Ammonia (NH3) is one of the fundamental pillars of the chemical industry nowadays. Compared with the traditional Haber-Bosch process that requires high energy consumption, the photocatalytic conversion of N-2 to NH3 under mild conditions is recognized as a sustainable and environmentally-friendly technology. However, the photocatalytic breakage of the N N bond in nitrogen (N-2) is a kinetically difficult process. Here, based on density functional theory (DFT) calculations, we report a novel and viable strategy to markedly boost the photocatalytic nitrogen fixation efficiency of InVO4 by tailoring its oxygen vacancies (V-O). InVO4 containing constructed V-O (V-O-InVO4) shows enhanced ammonia production rate, which can be attributed to the promoted N-2 adsorption, improved N-2 activation and decreased reaction barriers on the InVO4 surface, as evidenced by DFT simulations. Remarkably, the NH3 yield rate of the optimal V-O-InVO4 achieves up to 139.03 mu mol g(cat)(-1) h(-1), which is 5.33 times higher than that of InVO4 without additional V-O fabrication. The introduction of V-O largely suppresses the photogenerated charge carrier recombination and enhances visible light utilization, as revealed by photoluminescence and UV-vis absorption spectra, respectively, which correlate well with simulations. Notably, the low-valence V-4(+) induced by V-O is a more favorable active reaction site for N-2 adsorption, as revealed by the simulation results. This study not only provides a simple yet robust strategy to craft catalysts of high efficiency for photocatalysis, but also expands the mechanistic understanding about defect-mediated catalysis.

Automated summary

This study successfully improved the photocatalytic efficiency of nitrogen fixation by tailoring the oxygen vacancies in InVO4, resulting in a highly efficient catalyst. The introduction of oxygen vacancies not only suppressed the recombination of photogenerated charge carriers and enhanced visible light utilization, but also improved the adsorption and activation efficiency of nitrogen gas.