Enhancement of the generation of photocatalytic active species by loading copper ions on gold-nanoparticle-deposited titanium dioxide

• Generation of the active species on gold-nanoparticle-deposited TiO2 was promoted.
• Cu(II) loaded could suppress the recombination of photoexcited electrons and holes.
• Singlet oxygen and superoxide radical were increased by Cu(II) loading.
• Mechanism of the enhancement was proposed by considering the charge transfer process.

The photocatalytic performance of gold-nanoparticle-deposited titanium dioxide (AuNP/TiO2) photocatalyst was found to be improved significantly by loading Cu(II) ions, owing to the remarkable enhanced yield of singlet molecular oxygen (1O2) and superoxide radical (O2−), which were detected by near-infrared emission and chemiluminescence photometry, respectively. By loading Cu(II) the TiO2 conduction band electrons caused by the excitation of AuNP are trapped and then the time for reducing O2 to form O2− is prolonged. By the electron trap, the lifetime of holes in AuNP becomes also long to promote the formation of 1O2 by the oxidation of O2−.

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