Pt/TiO2 Prepared by Mechanochemistry Boosts Photocatalytic Production of Hydrogen

Abstract A series of Pt‐decorated TiO2 photocatalysts was synthesized via mechanochemical methods, varying Pt precursors (K2PtCl6, H2PtCl6, PtO2, Pt(NH3)4(NO3)2, Pt(acac)2, and PtCl2), Pt loadings, and milling conditions (time, energy, and ball‐to‐powder ratio). Hydrogen photoproduction was evaluated under dynamic conditions using gas‐phase ethanol–water mixtures and UV light. The optimal catalyst, prepared with K2PtCl6 at 0.33 wt.% Pt, exhibited the highest hydrogen production rate (7.4 mmol H2 h−1 gcat−1). Synthesis optimization via a Taguchi design of experiments identified low milling time, energy, and ball‐to‐powder ratio as key factors. Compared to a conventional Pt/TiO2 catalyst prepared by incipient wetness impregnation, the best ball‐milled sample showed 1.3 times higher hydrogen production and 1.2 times faster stabilization. Advanced characterization (HAADF‐STEM) revealed isolated Pt atoms in the ball‐milled catalyst, in contrast to small clusters in the reference. Post‐reaction analysis showed nanoparticle growth in both samples, but only the conventional sample developed fully formed nanoparticles (2.0 ± 0.8 nm). XPS detected a significant increase in surface K in the conventional catalyst due to a resurfacing effect. The superior performance of the ball‐milled sample is attributed to the stabilization of Pt single atoms and suppression of surface K restructuring, enhancing charge separation via modulation of the Schottky barrier.