Photocatalytic H2 generation on macro-mesoporous oxide-supported Pt nanoparticles

Abstract

A series of photocatalysts were prepared with crystalline macro-mesoporous oxides and Pt nanoparticles (Pt–TiO₂, Pt–Ta₂O₅, Pt–Nb₂O₅, Pt–ZrO₂, and Pt–Al₂O₃). Transmission electron microscopy, X-ray diffraction, and N₂ adsorption–desorption isotherms reveal that the oxides have prominent macro- and mesoporosity in the crystalline walls. The high surface area and crystalline walls of the oxides play significant roles in photocatalytic H₂ production. Pt–TiO₂ catalysts show enhanced photocatalytic water splitting efficiency for H₂ generation (solar energy conversion efficiency of 1.06%) under a 150 W and 1.5 AM solar simulator. Pt–Ta₂O₅ and Pt–Nb₂O₅ also generate noticeable photocatalytic activities of 0.21% and 0.16%, respectively. The enhanced photocatalytic activity is attributed to correct band alignment of the porous oxides with absorption in the UV-visible range, and ordered macro- and mesoporosity of the crystalline oxides for efficient charge transfer.