Enhancement of visible-light photocatalytic activity of Pt supported potassium niobate (Pt-KNbO3) by up-conversion luminescence agent (Er3+:Y3Al5O12) for hydrogen evolution from aqueous methanol solution

In this paper, a high effective up-conversion luminescence agent (Er3+:Y3Al5O12) is synthesized by sol–gel method, and then its corresponding visible-light photocatalysts (Er3+:Y3Al5O12/Pt-KNbO3) are successfully prepared by hydrothermal and direct mixing methods. For comparison, Er3+:Y3Al5O12, Pt-KNbO3 and Er3+:Y3Al5O12/Pt-KNbO3 are all characterized by XRD (X-ray diffractometer), SEM(scanning electron microscopy) and EDX(energy dispersive X-ray spectroscopy ). At first, the visible-light photocatalytic activity of Er3+:Y3Al5O12/Pt-KNbO3 is examined through photocatalytic hydrogen evolution from aqueous methanol solution under visible-light irradiation. Lastly, the influence factors such as Er3+:Y3Al5O12 and Pt-KNbO3 mass ratio, heat-treated temperature and initial pH value on the visible-light photocatalytic hydrogen evolution activity of Er3+:Y3Al5O12/Pt-KNbO3 are studied. Particularly, Er3+:Y3Al5O12/Pt-KNbO3 catalysts with 0.5:1.0 mass ratio heat-treated at 500 °C in aqueous methanol solution with initial pH = 6.0 show the highest photocatalytic activity in hydrogen evolution from aqueous methanol solution.