Engineering active intermetallic Pt–Zn sites <i>via</i> vapour–solid synthesis for photocatalytic hydrogen production

Intermetallic compounds hold great potential owing to the possibility of fine tuning their structure- and composition-dependent catalytic properties. Herein, a series of intermetallic Pt-Zn nanoparticles decorated on a TiO₂ support was designed <i>via</i> a novel and facile direct vapour-solid synthesis approach, and their co-catalytic performance towards the light-driven hydrogen evolution reaction (HER) was investigated. The intrinsic activity of Pt/TiO₂ was almost doubled <i>via</i> the addition of Zn and the formation of Pt₂₇-Zn₇₃/TiO₂, achieving a substantial increase in the apparent quantum yield (AQY) values up to 10.3%. In contrast to Pt-Zn intermetallic co-catalysts generally exhibiting higher HER rates, the interaction of Zn with surface defects of TiO₂ enhanced the catalyst stability, resulting in strongly suppressed deactivation. This work introduces intermetallic cocatalysts as promising systems, highlighting the influence of composition and structure on catalyst activity and providing future research directions.