Kok Hwa Lim

Publications (2)6.32 Total impact

• Article: Experimental and theoretical studies of Fe-doped TiO2 films prepared by peroxo sol-gel method

  Diana V. Wellia, Qing Chi Xu, Mahasin Alam Sk, Kok Hwa Lim, Tuti Mariana Lim, Timothy Thatt Yang Tan
  Applied Catalysis A General 07/2011; 401(1-2):98-105. · 3.90 Impact Factor
• Article: Transparent visible light activated C–N–F-codoped TiO2 films for self-cleaning applications

  Qing-chi Xu, Diana V. Wellia, Mahasin Alam Sk, Kok Hwa Lim, Joachim Say Chye Loo, Dai Wei Liao, Rose Amal and Timothy Thatt Yang Tan
  [show abstract] [hide abstract]
  ABSTRACT: The current work reports a potential technology for fabricating visible light activated doped TiO2 coatings for self-cleaning applications. Transparent C–N–F-codoped TiO2 films with enhanced visible light photocatalytic activity and non-light activated superwettability were successfully prepared by a simple layer-by-layer dip-coating method using TiO2 sol and NH4F methanol solution as precursors. The current coating method prevents the reactions of F− ions with the glass substrate and hence resulting in a uniform and transparent coating. It also creates TiO2 coating with high surface roughness without an additional pore-inducing agent and generates non-irradiated superhydrophilic surface. Contact angles of the C–N–F-codoped TiO2 films were 2.3–3.1° in the absence of any illumination and they rose slowly in the dark (<1.8° in 30 days). The C–N–F-codoped TiO2 films showed strong visible-light absorption and enhanced photocatalytic activity for stearic acid decomposition under visible light irradiation, which was 5 times higher than that of C-doped TiO2 film. Our DFT calculations also showed that increasing N:F doping ratio leads to band gap narrowing of TiO2.
  Journal of Photochemistry and Photobiology A Chemistry 02/2010; 210:181-187. · 2.42 Impact Factor