Hydrogen production from water splitting under UV light irradiation over Ag-loaded mesoporous-assembled TiO 2–ZrO 2 mixed oxide nanocrystal photocatalysts

Abstract

Hydrogen production from the photocatalytic water splitting reaction is very attractive because it is an environmentally friendly process, where hydrogen is produced from two abundantly renewable sources, i.e. water and solar energy, with the aid of photocatalysts. TiO 2 is the most widely investigated photocatalyst; however, it alone still exhibits low performance to photocatalytically produce hydrogen. Hence, the aim of this work focused on the enhanced photocatalytic hydrogen production over Ag-loaded mesoporous-assembled TiO 2–ZrO 2 mixed oxide nanocrystal photocatalysts under UV light irradiation. The TiO 2–ZrO 2 mixed oxides with various TiO 2-to-ZrO 2 molar ratios were synthesized by a sol–gel process with the aid of a structure-directing surfactant, followed by Ag loading via a photochemical deposition method. The influences of photocatalyst preparation parameters, i.e. calcination temperature, phase composition, and Ag loading, were studied. The results revealed that the mesoporous-assembled TiO 2–ZrO 2 mixed oxide nanocrystal photocatalyst with a TiO 2-to-ZrO 2 molar ratio of 93:7 calcined at 500 °C exhibited the highest photocatalytic hydrogen production activity, and the Ag loading of 0.5 wt.% further greatly enhanced the photocatalytic activity of such TiO 2–ZrO 2 mixed oxide photocatalyst.