Preparation of Ta3N5 Nanosheet by Nitridation of Monolayer Tantalum Oxide Nanosheet

Two-dimensional semiconducting materials have attracted attention as photocatalysts, electrode catalysts and electronic materials. However, preparation of metal nitride nanosheet is still a significant challenge. Here, we show a tantalum nitride (Ta3N5) nanosheet with a thickness of 1.5 nm prepared via tantalum oxide [TaO3](-) nanosheet derived from layered rubisium tantalum oxide (RbTaO3). The monolayer tantalum oxide nanosheet was converted to Ta3N5 nanosheet with a [110] preferred orientation in the in-plane direction during annealing under NH3 gas flow, and showed a photocatalytic activity for H-2 evolution under visible light illumination (550 nm). The H-2 evolution ratio of the ultrathin Ta3N5 nanosheet was much higher than that of bulk Ta3N5 prepared from Ta2O5 powder, indicating that nanosheet structure suppresses the recombination in the photocatalytic reaction.