A facile synthesis of AgxAu1−x/TiO2 photocatalysts with tunable surface plasmon resonance (SPR) frequency used for RhB photodegradation

A series of AgxAu1−x/TiO2 photocatalysts with tunable surface plasmon resonance (SPR) frequencies were successfully prepared via a facile photoreduction combined with a simple replacement reaction between Ag and Au3+ ions. These two reactions react synergistically, resulting in the formation of Ag-Au alloy on TiO2. The as-prepared AgxAu1−x/TiO2 plasmonic photocatalysts exhibiting different colors absorb the visible light with different wavelengths, improving the utilization efficiency of the incident light with distinct frequencies. For RhB degradation, these catalysts containing Ag-Au alloy show much higher visible light-responsive photocatalytic activity than the commercial P25 and the single supported Ag or Au catalysts. By mixing the catalysts AgxAu1−x/TiO2 with different SPR frequencies, the photocatalytic activity can be further improved due to the widened visible light absorption range.