Acid-base resistant ligand-modified molybdenum-sulfur clusters with enhanced photocatalytic activity towards hydrogen evolution

Studying the active sites associated with the hydrogen evolution reaction (HER) in molecular detail is challenging, but critical to the development of a high-performance catalyst for the generation of H-2, a carbon-free fuel derived from water. We report a well-defined molecule, (Mo3S7)-S-IV(MBTZ)(3)Br (MoS-MBTZ, where MBTZ = 2-mercaptobenzothiazole), which has a triangular fragment of molybdenum disulfide (MoS2). MoS-MBTZ displays excellent acid-base stability and survives for at least one month in solution at pH 1-14. Notably, the complex exhibits superior activity as a heterogeneous photocatalyst for the HER, producing H-2 at a rate of 101.81 mmol g(-1) h(-1), which is 16.3 and 188.5 times that of the organic ligand-free cluster (NEt4)(2)(Mo3S7Br6)-S-IV (MoS-Br) and commercial MoS2 under visible light irradiation (lambda >= 420 nm), respectively. Experimental results and theoretical calculations show that the edge and even the face sites of S atoms of the trimeric Mo-S units are activated significantly by coordination with MBTZ, as a result of the effect of MBTZ on the energy band structure and the facilitated separation and transfer of photogenerated carriers. This work provides a structurally precise model with which to explore the impact of an organic ligand on the photocatalytic HER activity and to reveal the structure-property relationships.

Automated summary

Studying the active sites associated with the hydrogen evolution reaction (HER) is crucial for developing a high-performance catalyst for generating carbon-free fuel H-2. This study presents a well-defined molecule (MoS-MBTZ) that acts as a heterogeneous photocatalyst for HER, producing H-2 at an exceptional rate. The findings demonstrate that the coordination of MBTZ activates the edge and face sites of the Mo-S units, improving the separation and transfer of photogenerated carriers.