The construction of a vanadium-doped polysulfide iron bimetallic active center for enhanced photocatalytic nitrogen fixation

Abstract

Inspired by natural nitrogen fixation, we constructed a metal–S mimetic biocatalyst using vanadium-doped iron polysulfide as the active center combined with g-C₃N₅, which is rich in nitrogen vacancies. While iron in polysulfide tends to act as the active site for nitrogen adsorption, the doped vanadium tends to act as the protonation center for adsorption of active water, and the two metals act synergistically to facilitate the photocatalytic nitrogen fixation process. The construction and addition of the vanadium-doped polysulfide active center resulted in a composite catalyst with superior structural stability and excellent visible light-driven performance relative to pure g-C₃N₅, with NH₃ yields of up to 1916.5 μmol h⁻¹ g_cat⁻¹ at the reaction temperature of 35 °C, 6.81 times higher than that of pure g-C₃N₅ (245.3 μmol h⁻¹ g_cat⁻¹). We believe that the construction of the vanadium-doped polysulfide iron bimetallic active center not only provides new ideas and directions for the study of environmentally friendly catalysts for biomimetic nitrogen fixation enzymes, but also for exploration of low energy consumption and green methods for mild nitrogen fixation.