Comparative investigation of hydrogen production over Ag-, Ni-, and Cu-loaded mesoporous-assembled TiO 2–ZrO 2 mixed oxide nanocrystal photocatalysts

Abstract

This work focused on the enhancement of photocatalytic hydrogen production activity under UV light irradiation of mesoporous-assembled 0.93TiO 2–0.07ZrO 2 mixed oxide nanocrystal photocatalysts (having the TiO 2-to-ZrO 2 molar ratio of 93:7) by non-precious metal (Ag, Ni, and Cu) loadings via a photochemical deposition method. The mesoporous-assembled 0.93TiO 2–0.07ZrO 2 mixed oxide was synthesized by a sol–gel process with the aid of a structure-directing surfactant prior to the metal loadings. The prepared photocatalysts were characterized by N 2 adsorption–desorption, scanning electron microscopy, transmission electron microscopy, X-ray energy dispersive analysis, X-ray diffraction, UV–visible spectroscopy, and H 2 chemisorption. The most efficient loaded metal was found to be Cu due to its suitable physical, chemical, and electrochemical properties with the 0.93TiO 2–0.07ZrO 2 mixed oxide-based photocatalyst. The 0.15 wt.% Cu-loaded 0.93TiO 2–0.07ZrO 2 mixed oxide photocatalyst exhibited the highest photocatalytic hydrogen production activity with a hydrogen production rate of 12.8 cm 3 h −1 g cat −1.