Preparation of RuO2/ZrO2/TaON Composite Photocatalyst and Its Photocatalytic Properties for Water Splitting Hydrogen Evolution

ZrO2/Ta2O5 composite oxide powders in a fine particle size were prepared by the controlled hydrolysis method, and subsequently nitrided in a flowing ammonia at a flow rate of 90 mL/min at 850 degrees C for 10 h, to form ZrO2/TaON. Then, RuO2 co-catalyst was immobilized on the ZrO2/TaON via an impregnation method. The samples were characterized with XRD, SEM, TEM and UV-Vis diffuse reflectance spectroscope. Both ZrO2 and RuO2 were in a crystallite size of ca. 10 nm, while TaON was in a crystallite size of ca. 25 nm, and composite photocatalysts absorbed the visible light at wavelength less than 500 nm. The introducing of ZrO2 reduced the defect density of TaON and increased the specific surface area of TaON. The photocatalytic efficiency of composite photocatalysts was quantitatively evaluated via determining the photo-current density as well as in the water splitting hydrogen evolution reaction. The sample with a RuO2 loading of 2.0 wt% showed the photocurrent of 0.6 mA/cm(2) at a bias voltage of 0.6 V, and H-2 evolution rate as high as 6.0 mu mol/h under a Xe lamp irradiation.