Kunlanan Kiatkittipong

Publications (2)4.53 Total impact

• Article: Hydrothermally synthesized titanate nanostructures: impact of heat treatment on particle characteristics and photocatalytic properties.

  Kunlanan Kiatkittipong, Jason Scott, Rose Amal
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  ABSTRACT: The role titanate particle structure plays in governing its characteristics upon calcining and their ensuing influence on photocatalytic performance was investigated. Titanate nanotubes and nanoribbons were prepared by hydrothermal treatment of Aeroxide P25 and then calcined at temperatures in the range 200 - 800 °C. Heat treatment directly transformed the nanotubes to anatase while nanoribbon transformation to anatase occurred via a TiO(2)(B) intermediate phase. The nanoribbon structure also provided an increased resistance to sintering, allowing for retention of the original {010} facet of the titanate nanosheets up to 800 °C. The changing material properties with calcining were found to influence the capacity of the particles to photodegrade oxalic acid and methanol. The nanotubes provided an optimum photoactivity following calcination at 500 °C with this point representing a transition between the relative dominance of crystal phase and surface area on performance. The comparatively smaller initial surface area of the nanoribbons consigned this characteristic to a secondary role in influencing photoactivity with the changes to crystal phase dominating the continually improving performance with calcination up to 800 °C. The structural stability imparted by the nanoribbon architecture during calcination, in particular its retention of the {010} facet at temperatures >700 °C, advanced its photocatalytic performance compared with the nanotubes. This was especially the case for methanol photooxidation whose primary degradation mechanism relies on hydroxyl radical attack and was facilitated by the {010} facet. The effect was not as pronounced for oxalic acid due to its higher adsorption on TiO(2) and therefore greater susceptibility to oxidation by photogenerated holes. This study demonstrates that, apart from modulating sintering effects and changes to crystal phase, the titanate nanostructure influences particle crystallography which can be beneficial for photocatalytic performance.
  ACS Applied Materials & Interfaces 09/2011; 3(10):3988-96. · 4.53 Impact Factor
• Article: Understanding Hydrothermal Titanate Nanoribbon Formation

  Kunlanan Kiatkittipong, Changhui Ye, Jason Scott, Rose Amal
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  ABSTRACT: Titanate nanoribbons were prepared by hydrothermal treatment of neat TiO2 P25 with 10 M NaOH at 200 °C. Hydrothermal aging times were varied to assist with understanding the transformation process while the impact of postsynthesis acid washing on nanoribbon formation kinetics was assessed. Nanoribbon evolution was observed to occur via the formation of intermediate amorphous titanate particles. The final nanoribbon product was found to comprise a layered titanate framework with sodium cations interspersed between the sheets. Acid washing served to exchange the Na+ with H+ to give H2Ti3O7. Moreover, acid washing accelerated nanoribbon formation, providing a well-defined (i.e., no amorphous particles) nanoribbon sample after 15 h compared to 40 h when acid washing was not used. The difference in formation rates was attributed to interlayer formation of the intermediates in the hydrogen bond array (i.e., Ti−O−H) during H2Ti3O7 being faster than intermediate formation in the sodium bond array (i.e., Ti−O−Na). Acid washing of the nanoribbon samples after extended hydrothermal synthesis times (>24 h) led to fragmenting of the structure.
  06/2010;