Direct Anchoring of Molybdenum Sulfide Molecular Catalysts on Antimony Selenide Photocathodes for Solar Hydrogen Production

Molybdenum sulfide serves as an effective nonprecious
metal catalyst
for hydrogen evolution, primarily active at edge sites with unsaturated
molybdenum sites or terminal disulfides. To improve the activity at
a low loading density, two molybdenum sulfide clusters, [Mo3S4]4+ and [Mo3S13]2–, were investigated. The Mo3Sx molecular catalysts were heterogenized on Sb2Se3 with a simple soaking treatment, resulting
in a thin catalyst layer of only a few nanometers that gave up to
20 mA cm–2 under one sun illumination. Both [Mo3S4]4+ and [Mo3S13]2– exhibit catalytic activities on Sb2Se3, with [Mo3S13]2– emerging as the superior catalyst, demonstrating enhanced photovoltage
and an average faradaic efficiency of 100% for hydrogen evolution.
This superiority is attributed to the effective loading and higher
catalytic activity of [Mo3S13]2– on the Sb2Se3 surface, validated by X-ray
photoelectron and Raman spectroscopy.