Enhanced Nitrogen Photofixation over LaFeO₃ via Acid Treatment

Abstract

The N2 photofixation presents a green and eco-friendly ammonia synthesis approach. However, present strategies for light-induced N2 activation suffer from low efficiency and instability, largely hindering the development of this technology. Herein, we report the LaFeO3 co-optimization of N2 activation as well as subsequent photoinduced protonation with the further phosphate acid treatment. Efficient ammonia evolution rate reached 250 μmol g–1 h–1 over LaFeO3 under simulated sunlight with appropriate acid treatment. The enhancement of phosphate modified samples was mainly attributed to the “pull and push” effect. The hydrogen bonding centers and transition metals (Fe) served as two separation active sites, which improves the adsorption and activation of dinitrogen. In addition, the facilitation of H2O dissociation was also achieved after phosphate modification. These results suggested an alternative N2 photofixation strategy of traditional organic and precious metallic additives for efficient ammonia synthesis.