Preparation of Visible-light Responsive Rutile-TiO₂(110) Wafer with Well-defined Surface by Chromium and Antimony Codoping

Abstract

Transition-metal doping for titanium dioxide (TiO₂) is attracting attention for the study of visible-light responsive photocatalyst. Its photocatalytic properties were investigated via various spectroscopic approaches, though surface studies had not yet progressed owing to the difficulty in obtaining its well-defined surface. In this report, we propose that a well-defined crystalline TiO₂(110) surface may be obtained by the codoping of chromium (Cr) and antimony (Sb) with commercially available wafers. Cr and Sb are codoped by a solid-state reaction of TiO₂(110) wafer and dopant powder. The prepared wafer exhibited visible-light responsivity on absorption below wavelengths of 600 nm. The surface morphology characterization, performed by atomic force microscopy (AFM) revealed that the Cr and Sb codoped TiO₂(110) surface has a well crystallized step-terrace structure that is atomically flat, while monodoped TiO₂(110) surface does not. The codoping of Cr and Sb with TiO₂(110) wafer should contributes towards retaining the stable rutile-TiO₂ lattice structure and produces a well-defined TiO₂(110) surface structure with visible-light responsive characteristics.