Photocatalytic performance of Pr/In/Nd composite oxides synthesized by solid state reaction

Pr/In/Nd composite oxides with different Pr/In/Nd ratios were successfully prepared using a simple solid state reaction at 873   K. The composites were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area measurements, photoluminescence (PL) spectra and UV–vis diffuse reflection spectroscopy (UV–vis DRS). The photocatalytic activity of Pr/In/Nd composite oxides was investigated by the degradation of methyl orange (MO) in an aqueous solution under UV and visible light irradiation. It is found that compared with pure In 2 O 3 , the absorption intensity of the Pr/In/Nd composite oxide (Pr/In/Nd=1:8:1) increases in the 200–800   nm light region and the absorption edge has a shift to longer wavelength. In addition, the Pr/In/Nd composite oxide (Pr/In/Nd=1:8:1) shows higher UV and visible light photocatalytic activities than pure In 2 O 3 . The remarkably enhanced photocatalytic activities could be mainly attributed to the fact that proper introduction of Pr 2 O 3 and Nd 2 O 5 increased the BET surface area of In 2 O 3 , improved the separation efficiency of photogenerated electrons and holes, and enhanced the absorption intensity in 200–800   nm light region. The effect of various radical scavengers on the degradation of MO showed that OH, O 2 − , h + and H 2 O 2 , especially O 2 − , jointly dominated the photodegradation process of MO under UV light irradiation.