Photocatalytic H2 evolution properties of K0.5Na0.5NbO3 (KNN) with halloysite nanotubes

By the solid phase reaction method, pure KNN and KNN with different proportions halloysite nanotubes (HNTs) were prepared to study the photocatalytic hydrogen evolution performance under the UV light irradiation. The band gaps of KNN with HNTs are narrower than that of pure KNN. The absorbance of KNN in the ultraviolet region is significantly enhanced by the incorporation of HNTs, where the absorbance in the 200-300 nm region increased about 2 times. Compared with KNN, the conduction band edge of KNN-5wt%HNTs reduced from −1.13 eV to −1.18 eV, showing stronger reducing ability. The H 2 production rate of KNN with HNTs is much higher than that of the raw KNN without HNTs. The best H 2 production rate of KNN-5wt%HNTs is 31.28 μmol•g −1 •h −1 , approximate 4.48 times as high as the rate of pure KNN (6.98 μmol•g −1 •h −1 ), suggesting appropriate addition of HNTs can efficiently improve the H 2 production efficiency.