Plasmonic Ag decorated CdMoO 4 as an efficient photocatalyst for solar hydrogen production.

The synthesis of Ag-nanoparticle-decorated CdMoO 4 and its photocatalytic activity towards hydrogen generation under sunlight has been demonstrated. The CdMoO 4 samples were synthesized by a simple hydrothermal approach in which Ag nanoparticles were in situ decorated on the surface of CdMoO 4 . A morphological study showed that 5 nm spherical Ag nanoparticles were homogeneously distributed on the surface of CdMoO 4 particles. The UV/DRS spectra show that the band gap of CdMoO 4 was narrowed by the incorporation of a small amount of Ag nanoparticles. The surface plasmonic effect of Ag shows broad absorption in the visible region. The enhanced photocatalytic hydrogen production activities of all the samples were evaluated by using methanol as a sacrificial reagent in water under natural sunlight conditions. The results suggest that the rate of photocatalytic hydrogen production using CdMoO 4 can be significantly improved by loading 2% Ag nanoparticles: i.e. 2465 μmol h -1 g -1 for a 15 mg catalyst. The strong excitation of surface plasmon resonance (SPR) absorption by the Ag nanoparticles was found in the Ag-loaded samples. In this system, the role of Ag nanoparticles on the surface of CdMoO 4 has been discussed. In particular, the SPR effect is responsible for higher hydrogen evolution under natural sunlight because of broad absorption in the visible region. The current study could provide new insights for designing metal/semiconductor interface systems to harvest solar light for solar fuel generation.