Visible light active Bi3TaO7 nanosheets for water splitting

Abstract

Tantalate semiconductors are potential photocatalysts for hydrogen generation via photocatalytic water splitting reaction because the conduction band of tantalates is composed of the tantalum 5d orbital, which is located at a more negative potential than that of the H⁺/H₂ half reaction, i.e., 0.0 V vs. NHE. Bi₃TaO₇ is a stable tantalate under acidic or alkaline conditions, with a band gap suitable for visible light absorption. However, the photocatalytic properties of Bi₃TaO₇ are only reported based on the dye degradation reactions, probably due to the fast electron/hole recombination losses. 2D crystal-like nanosheets with a thickness of a few nanometers show unique features such as high carrier mobility, the quantum Hall effect, high specific surface area, and excellent electrical/thermal conductivity. 2D structures can also enhance the photocatalytic properties because photo-generated charge carriers in nanosheets are less prone to fast recombinations as compared to their bulk counterparts. In this study, nanosheets of Bi₃TaO₇ are produced by a liquid exfoliation method and the photocatalytic hydrogen generation reaction is investigated for both the as-synthesized Bi₃TaO₇ nanoparticles and Bi₃TaO₇ nanosheets.