ACS Nano http://doi.org/n52 (2013)

Credit: © 2013 ACS

Titanium dioxide has been shown to be suitable for photocatalytic oxidation with molecular oxygen, but one of the main issues for its practical applicability is its modest catalytic activity under visible light irradiation. Now Yasuhiro Shiraishi and colleagues report that platinum–copper bimetallic alloy nanoparticles supported on anatase TiO2 exhibit enhanced photocatalytic behaviour for aerobic oxidation under visible light irradiation. The improved photocatalytic activity (17% apparent quantum yield under 550-nm monochromatic light) results from the electronic excitation of Pt atoms followed by the transfer of activated electrons to the anatase conduction band. Copper alloying with platinum lowers both the Schottky barrier height and work function of nanoparticles created at the particle/anatase heterojunction. The photocatalytic activity is also found to be related to the size of the alloy particles: those in the 3–5-nm-diameter range exhibit improved photocatalytic performance for selective and efficient aerobic oxidation of alcohols at ambient temperature.