Nitrogen activation and surface charge regulation for enhancing the visible-light-driven N₂ fixation over MoS₂/UiO-66(SH)₂

A series of dehydrated MoS2/UiO-66(SH)(2) (MS/UiS) composites has been prepared as photocatalysts for N-2 fixation. Typically, 10% MS/UiS exhibits the best performance with an NH4+ yield rate of 54.08 mu mol center dot g(-1)center dot h(-1). N-15 isotope test confirmed that the sample 10% MS/UiS was most effective for reducing N-2 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 N-2. The photogenerated electrons would transfer to the unsaturated ZrO 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 N-2 is reduced to ammonia by the synergistic effect of protonated hydrogen and photogenerated electrons. Finally, a possible N-2 fixation mechanism is proposed which emphasizes the significant roles of nitrogen activation and interface interaction in composites photocatalyst for improving photocatalytic performance.