Enhanced photocatalytic activity of photocatalyst coatings by heat treatment in carbon atmosphere

• We report the fabrication of TiCxOy coatings with highly photoactive activity.
• Nano-bump structure is with mixed crystal of titanium oxycarbide and rutile TiO2.
• Heat treatment in carbon atmosphere is a simple and useful method for photocatalyst.
• Heat treatment in carbon atmosphere narrows the band gap to 1.48 eV.

An inexpensive and effective method is used to enhance the photocatalytic activity of photocatalyst coatings by heat treatment in carbon atmosphere. Nano-bump structure with mixed crystal of titanium oxycarbide and rutile TiO2 form on the surface of Ti coatings, during heat treatment in carbon atmosphere. In the case of heat treatment in air, micro-column structure with rutile TiO2 form on the surface of Ti coatings. The change of surface morphologies substantially increases the accessible surface area. During heat treatment in carbon atmosphere, oxygen vacancies generated in the lattice of mixed crystal are in favor of narrowing band gap. The narrowed band gap effectively benefits the generation of more photo-induced electrons and holes to enhance the photocatalytic activity under both ultraviolet and visible-light irradiation, compared with the pristine TiO2 coatings.

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