Patent ID: 8445401

Claim:
A method for manufacturing rutile-structured titanium dioxide having excellent photocatalytic activity, comprising: (i) applying a voltage of 100 V or higher and performing anodic oxidation for a duration of 2 minutes or longer on a surface of titanium or a titanium alloy base material in an electrolyte of sulfuric acid concentration ranging from 2.6 wt % to 14.1 wt % to produce a film of rutile structured titanium dioxide on the surface of the titanium or titanium alloy base material; and performing annealing in the atmosphere at a temperature ranging from 400° C. to 1000° C. or higher on said film produced or (ii) performing anodic oxidation for a duration 2 minutes or longer on the surface of a titanium or a titanium alloy base material, in an electrolyte of sulfuric acid concentration ranging from 2.6 wt % to 14.1 wt %, under conditions of current density of 25 mA/cm2 or higher to produce a film of rutile structured titanium dioxide on the surface of the titanium or titanium alloy base material; and performing annealing in the atmosphere at a temperature ranging from 400° C. to 1000° C. or higher on said film produced.