• Xi, F.; Bozheyev, F.; Han, X.; Rusu, M.; Rappich, J.; Abdi, F.; Bogdanoff, P.; Kaltsoyannis, N.; Fiechter, S.: Enhancing Hydrogen Evolution Reaction via Synergistic Interaction between the [Mo3S13]2 Cluster Co-Catalyst and WSe2 Photocathode. ACS Applied Materials & Interfaces 14 (2022), p. 52815–52824

Open Accesn Version

A thiomolybdate [Mo3S13]2– nanocluster is a promising catalyst for hydrogen evolution reaction (HER) due to the high number of active edge sites. In this work, thiomolybdate cluster films are prepared by spin-coating of a (NH4)2Mo3S13 solution both on FTO glass substrates as hydrogen evolving electrodes and on highly 00.1-textured WSe2 for photoelectrochemical water splitting. As an electrocatalyst, [Mo3S13]2– clusters demonstrate a low overpotential of 220 mV at 10 mA cm–2 in 0.5 M H2SO4 electrolyte (pH 0.3) and remain structurally stable during the electrochemical cycling as revealed by in situ Raman spectroscopy. Moreover, as a co-catalyst on WSe2, [Mo3S13]2– clusters enhance the photocurrent substantially by more than two orders of magnitude (from 0.02 to 2.8 mA cm–2 at 0 V vs RHE). The synergistic interactions between the photoelectrode and catalyst, i.e., surface passivation and band bending modification by the [Mo3S13]2– cluster film, promoted HER catalytic activity of [Mo3S13]2– clusters influenced by the WSe2 support, are revealed by intensity-modulated photocurrent spectroscopy and density functional theory calculations, respectively. The band alignment of the WSe2/[Mo3S13]2– heterojunction, which facilitates the electron injection, is determined by correlating UV–vis with photoelectron yield spectroscopy results.