From Well-Defined Clusters to Functional Materials: Molecular Engineering of Amorphous Molybdenum Sulfides for Hydrogen Evolution Electrocatalysis

Abstract

Developing precious-metal-free electrocatalysts for the hydrogen evolution reaction (HER) is crucial to establishing H 2 produced from renewable energy sources as an alternative energy carrier to fossil fuels. Amorphous molybdenum sulfide-based materials are promising candidates that provide highly active HER electrocatalysts by introducing active sites at both the edge positions and the typically inactive basal planes. Herein, we report an innovative bottom-up synthesis of amorphous molybdenum sulfides using molecular complexes with Mo 3 S 4 and Mo 3 S 7 cluster cores as building entities. The ability to control the precursor of choice has made it viable to enhance the HER activity of these materials. Furthermore, the tunability of the atomic composition of the molecular cluster precursors allows the modification of the derived materials with atomic-scale precision, enabling us to track the synthesis mechanism and, in combination with Density Functional Theory (DFT) calculations, to decipher the nature of the HER active sites.

Optimizing Amorphous Molybdenum Sulfide Thin Film Electrocatalysts: Trade-Off between Specific Activity and Microscopic Porosity

“…Despite the great promise of a-MoS x , the origin of its high catalytic activity, as well as the structure–activity relations and surface spatial heterogeneity of a-MoS x , is underexplored. ,− In fact, the exact structure of a-MoS x and therefore the possible bonding environments of the S atomsis still under debate . Experimental and theoretical studies have identified that the HER activity of a-MoS x samples is intimately linked to the S types present, making this information vital to aid in the systematic design of high-performance a-MoS x catalysts. − Further, there is a consensus within the literature that thicker a-MoS x films show higher activity; however, such measurements are taken macroscopically only and have not been fully rationalized. , …”