Nitrogen activation and surface charge regulation for enhancing the visible-light-driven N₂ fixation over...

A series of dehydrated MoS₂/UiO-66(SH)₂ (MS/UiS) composites has been prepared as photocatalysts for N₂ fixation. Typically, 10% MS/UiS exhibits the best performance with an NH₄⁺ yield rate of 54.08 μmol∙g^-1∙h^-1. ¹⁵N isotope test confirmed that the sample 10% MS/UiS was most effective for reducing N₂ to ammonia. Such enhanced activity was due to the presence of abundant unsaturated Zr and Mo sites which would synergistically promote the adsorption and activation of N₂. The photogenerated electrons would transfer to the unsaturated Zr-O clusters while part of photogenerated electrons at the interface migrate to MS via Mo^VI-O interactions between MS and UiS. These two electron transfer pathways effectively promote the separation of photogenerated carriers. The activated N₂ is reduced to ammonia by the synergistic effect of protonated hydrogen and photogenerated electrons. Finally, a possible N₂ fixation mechanism is proposed which emphasizes the significant roles of nitrogen activation and interface interaction in composites photocatalyst for improving photocatalytic performance.