Visible light driven photocatalytic activity of palladium nanoparticles assisted potassium niobate microrods

Abstract

KNbO3 nano/micro materials possess unique structure with fascinating multifunctional properties. Particularly, it acts as promising catalytic materials in the UV region. In order to improve the visible light catalytic activity, noble metals addition is widely employed. In this work, we report on the structural, morphological, optical and visible light active photocatalytic properties of potassium niobate (KNbO3) and 0.5 and 1.0 wt% palladium nanoparticles (Pd NPs) assisted KNbO3 microrods. X-ray diffraction and Raman spectra confirmed the formation of orthorhombic structure of KNbO3. The grain growth orientation, interplanar spacing and crystalline nature of the Pd NPs, KNbO3 and Pd NPs (1.0 wt%) assisted KNbO3 were confirmed by transmission electron microscopy. The UV–visible diffuse reflectance spectra revealed variation in the absorption edge (390–420 nm) and band gap values (3.28–3.24 eV). The photoluminescence spectra of the prepared KNbO3 samples showed visible light emission (485–544 nm) at room temperature. In the present study, a high photocatalytic dye degradation efficiency (2 times greater than that of KNbO3) and high reaction rate constant (~15 times that of KNbO3) for Pd NPs (1.0 wt%) assisted KNbO3 microrods were obtained. It is concluded that the Pd NPs (1.0 wt%) assisted KNbO3 microrods with high BET surface area (11.78 m2 g−1) leads to efficient electron-hole pair separation which enhances photocatalytic degradation of RhB dye aqueous solution under visible light region.