[Mo3 S13 ]2- as a Model System for Hydrogen Evolution Catalysis by MoSx : Probing Protonation Sites in the Gas Phase by Infrared Multiple Photon Dissociation Spectroscopy

Angew Chem Int Ed Engl. 2021 Mar 1;60(10):5074-5077. doi: 10.1002/anie.202014449. Epub 2021 Jan 26.

Abstract

Materials based on molybdenum sulfide are known as efficient hydrogen evolution reaction (HER) catalysts. As the binding site for H atoms on molybdenum sulfides for the catalytic process is under debate, [HMo3 S13 ]- is an interesting molecular model system to address this question. Herein, we probe the [HMo3 S13 ]- cluster in the gas phase by coupling Fourier-transform ion-cyclotron-resonance mass spectrometry (FT-ICR MS) with infrared multiple photon dissociation (IRMPD) spectroscopy. Our investigations show one distinct S-H stretching vibration at 2450 cm-1 . Thermochemical arguments based on DFT calculations strongly suggest a terminal disulfide unit as the H adsorption site.

Keywords: IRMPD spectroscopy; hydrogen evolution reaction; mass spectrometry; molybdenum sulfide clusters.