Hydrogen Production by Photocatalytic Water Splitting over Pt/TiO₂ Nanosheets with Exposed (001) Facets

TLDR

The study examined how Pt loading affects photocatalytic hydrogen production from ethanol aqueous solutions using Pt/TiO₂ nanosheets with exposed (001) facets. Pt/TiO₂ nanosheets were synthesized via hydrothermal treatment of Ti(OC₄H₉)₄–HF–H₂O, followed by photochemical Pt deposition under xenon lamp irradiation, and characterized by TEM, XRD, XPS, BET, UV–vis, and PL to confirm surface •OH generation. Pt loading significantly increased hydrogen evolution rates, with 2 wt % Pt yielding the highest activity, and fluorinated TiO₂ nanosheets outperformed Degussa P25 and pure TiO₂ nanoparticles due to synergistic fluorination and exposed (001) facets.

Abstract

Pt/TiO2 nanosheets with exposed (001) facets were fabricated by a simple hydrothermal route in a Ti(OC4H9)4-HF-H2O mixed solution followed by a photochemical reduction deposition of Pt nanoparticles on TiO2 nanosheets under xenon lamp irradiation. The prepared samples were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, nitrogen adsorption−desorption isotherms, UV−vis diffuse reflectance spectroscopy, and photoluminescence (PL) spectroscopy. Production of •OH radicals on the TiO2 surface was detected by the PL technique using coumarin as a probe molecule. The effects of Pt loading on the rates of photocatalytic hydrogen production of the as-prepared samples in ethanol aqueous solution were investigated and discussed. The results showed that the photocatalytic hydrogen production rates of TiO2 nanosheets from the ethanol aqueous solutions were significantly enhanced by loaded Pt on the TiO2 nanosheets, and the latter with a 2 wt % of deposited Pt exhibited the highest photocatalytic activity. All fluorinated TiO2 nanosheets exhibited much higher photocatalytic activity than Degussa P25 TiO2 and pure TiO2 nanoparticles prepared in pure water due to the synergistic effect of surface fluorination and exposed (001) facets.