Photoelectrochemical investigation of k₂ti₆o₁₃ thin film prepared by sol-gel method

The sol-gel method was used to prepare potassium hexatitanate and titania thin films on indium-tin oxide (ITO) substrate by dip-coating. With this method, the connection between K₂Ti₆O₁₃ film and ITO glass substrate was strong and maintained a good electrical contact. Electrochemical method combined with ultraviolet-visible light absorption spectrometry was used to ascertain the electronic band structure of K₂Ti₆O₁₃ film. TiO₂ film was used to verify the feasibility of this method and compared with K₂Ti₆O₁₃ film as a reference system of structure and performance characteristic. The results show that the band gap energy of K₂Ti₆O₁₃ film electrode estimated from the ultraviolet spectrum was 3.05 eV which is lower than that of K₂Ti₆O₁₃ particle (3.45 eV) and TiO₂ film (3.22 eV). K₂Ti₆O₁₃ film possessed visible light response capability. The lower edge of the conduction band of the potassium hexatitanate was approximately-0.77 V (vs. NHE) lower than that of anatase (-0.61 V vs. NHE), which indicates that K₂Ti₂O₁₃ film electrode possesses stronger reducibility. The potassium hexatitanate had the feasibility of hydrogen production from water photolysis. The electrochemical measurement also reveals that K₂Ti₆O₁₃ is a stable photocatalyst with effective separation of photogenerated charge carriers. Consequently, the K₂Ti₆O₁₃ film is a promising material in the field of hydrogen manufacturing with visible light.