Monodisperse mesoporous Ta2O5 colloidal spheres as a highly effective photocatalyst for hydrogen production

Abstract

Catalysts based on porous colloidal spheres not only effectively overcome solid–liquid separation, but also ensure large amount of active sites in catalytic reactions. Therefore, the development of synthetic technology to prepare porous colloidal spheres is highly desired but it is also highly challenging. In this work, we showed a high-yield and low-cost reaction route to prepare crystallized porous tantalum pentoxide spheres (CPTS) with particle diameters of ca. 400–500 nm by a combination of antisolvent precipitation method and subsequent hydrothermal treatment. The as-prepared porous spheres were composed of Ta2O5 nanocrystals and had a large specific surface area of up to 265.4 m2/g. By treating CPTS with ammonium fluoride or ammonia, N or F doped porous Ta2O5 spheres photocatalysts were successfully obtained, while the mesoporosity and morphology of CPTS were well retained. The anion-doped CPTS exhibited excellent photocatalytic activity for hydrogen evolution under UV irradiation due to their larger surface area and controlled morphology compared with previously reported Ta2O5 fine particles after doping with impurity ions (F and N).