Comparative investigation of hydrogen production over Ag-, Ni-, and Cu-loaded mesoporous-assembled TiO2–ZrO2 mixed oxide nanocrystal photocatalysts

This work focused on the enhancement of photocatalytic hydrogen production activity under UV light irradiation of mesoporous-assembled 0.93TiO2–0.07ZrO2 mixed oxide nanocrystal photocatalysts (having the TiO2-to-ZrO2 molar ratio of 93:7) by non-precious metal (Ag, Ni, and Cu) loadings via a photochemical deposition method. The mesoporous-assembled 0.93TiO2–0.07ZrO2 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 N2 adsorption–desorption, scanning electron microscopy, transmission electron microscopy, X-ray energy dispersive analysis, X-ray diffraction, UV–visible spectroscopy, and H2 chemisorption. The most efficient loaded metal was found to be Cu due to its suitable physical, chemical, and electrochemical properties with the 0.93TiO2–0.07ZrO2 mixed oxide-based photocatalyst. The 0.15 wt.% Cu-loaded 0.93TiO2–0.07ZrO2 mixed oxide photocatalyst exhibited the highest photocatalytic hydrogen production activity with a hydrogen production rate of 12.8 cm3 h−1 gcat−1.

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► Ag, Ni, and Cu loadings on 0.93TiO2–0.07ZrO2 mixed oxide were achieved via photochemical deposition.
► The photocatalytic H2 production activity of the loaded 0.93TiO2–0.07ZrO2 mixed oxides was investigated.
► The photocatalytic activity enhancement was attained in the following order: Cu > Ni > Ag.
► The properties of these metals were related to their photocatalytic activity enhancement.