Homostructural Ta3N5 nanotube/nanoparticle photoanodes for highly efficient solar-driven water splitting

Abstract

Herein, we demonstrated a one-step ammonia treatment for fabricating homostructural Ta3N5 nanotube/nanoparticle photoanodes with a top-open structure. Compared with the relatively low activities of traditional Ta3N5 nanotube photoanode, this homo-photoanode exhibited a remarkably enhanced photocurrent density (1.58 mA cm−2 at 1.23 V vs. reversible hydrogen electrode (RHE)). Moreover, after the decoration of Co(OH)x cocatalyst, the photocurrent density could be further increased up to 8.73 mA cm−2 at 1.23 VRHE, accompanying with the significantly improved water oxidation stability as well as an evident negative shift of onset-potential (200 mV). More detailed studies reveal that the significantly promoted PEC activities should be attributed to the matched bandgaps between Ta3N5 nanotube and nanoparticle as well as the ordered top-open nanoarchitecture, which could accelerate charge separation and provide more active sites for water oxidation. Thereby, the construction of homostructural semiconductor photoanodes should be highly promising for promoting the development of PEC water splitting for practical applications.