One-pot soft-templating method to synthesize crystalline mesoporous tantalum oxide and its photocatalytic activity for overall water splitting

Crystalline mesoporous Ta₂O₅ has been successfully synthesized by a one-pot route using P-123 as the structure directing agent (SDA). A series of crystalline mesoporous Ta₂O₅ samples has been prepared by changing the calcination temperature. The surface area decreased and the pore size increased with the increasing calcination temperature, which were the results of crystallite growth. At the same time, the pore volume was well maintained, which means limited shrinkage during the calcination of elevated temperature. The porous structure and crystal structure of as-synthesized mesoporous Ta₂O₅ were characterized by XRD, TG-DTA, SEM, TEM, and N₂ sorption techniques. The photocatalytic activity of the as-synthesized mesoporous Ta₂O₅ with the cocatalyst NiO_x for overall water splitting under ultraviolet (UV) light irradiation was systematically evaluated. The photocatalytic activity of crystalline mesoporous Ta₂O₅ showed about 3 times that of commercial Ta₂O₅ powder and 22 times that of amorphous mesoporous Ta₂O₅.