Electrocatalytic performance of Ba-doped TiO2 hollow spheres in water electrolysis

Barium doped titania hollow sphere catalysts of various compositions were prepared and their electrocatalytic performance was evaluated in acidic media. Titania hollow sphere particles were prepared using poly (styrene-methacrylic acid) latex as template material, and BaCl2 was used precursor material during barium doping over spheres. The morphology and structure of Ba/TiO2 hollow spheres were characterized by BET, XRD, TGA and TEM analysis. XRD results had confirmed the presence of rutile TiO2 and BaTiO3 phases in the catalysts. The catalysts have shown almost similar surface area values (around 97 m(2)/g) irrespective of their compositions. On the other hand, surface area values were diminished remarkably with rise in the calcination temperatures. In TEM images, hollow sphere formation with uniform layer of barium over the spheres could clearly be observed. Diameter of Ba-doped TiO2 hollow sphere was found 0.4-0.5 mu m irrespective of the variation in calcination temperatures. In cyclic voltammograms, both the hydrogen and oxygen evolution peaks were present for all the hollow sphere samples; although the peak positions had changed to some extent for few samples. Anodic polarization curves have shown 60 mA cm(-2) current density for 20 wt% Ba/TiO2 hollow sphere sample. Tafel slope is revealed as 122 mV for the same electrocatalyst. Barium doped titania hollow spheres have also shown long time electrocatalytic stability in acid solution. (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.