Chromium-doped bismuth titanatenanosheets as enhanced visible-light photocatalysts with a high percentage of reactive {110} facets

Abstract

Single-crystalline chromium doped bismuth titanate (Bi₄Ti_3−xCr_xO₁₂, x = 0.0–0.5) nanosheets with exposed {110} facets have been synthesized via a facile hydrothermal process. The Bi₄Ti_3−xCr_xO₁₂nanosheets possess well-defined tetragonal shapes with landscape dimension of 100–300 nm and thickness of 10–30 nm. The in-plane surfaces of the nanosheets lies on {001}, and the side surfaces are (110) and (10). Extension of the light absorption from the ultraviolet region to the visible-light region arises from the Cr 2p levels confirmed by XPS spectra. The Bi₄Ti_2.6Cr_0.4O₁₂ nanosheets with high stability showed the highest photocatalytic performance of H₂ evolution from water under visible-light irradiation. Furthermore, the heterostructures by using the NiO_x nanoparticles tightly coupled on the surface of Bi₄Ti_2.6Cr_0.4O₁₂ nanosheets, exhibited an enhanced photocatalytic activity due to the decrease in the recombination rate of the photoinduced electrons and holes, demonstrating that NiO_x/Bi₄Ti_2.6Cr_0.4O₁₂ nanosheet is a promising candidate as a visible light photocatalyst.