Electrochemical Fabrication of TiO2-Au Nanocomposites

Nanocomposites comprised of electrosynthesized/annealed TiO2 on indium tin oxide substrates, using the electrogeneration of base method, followed by electrodeposited gold clusters are presented, and their photoelectrochemical response is examined. The TiO2 films are nodular with a rough morphology. Gold nanoparticles were electrodeposited onto the electrogenerated TiO2 with galvanostatic pulses. A step photoresponse analysis was employed to characterize the photoelectrochemical behavior of three different forms of the TiO2 -Au composite: (i) TiO2 decorated with Au nanoparticles, TiO2/Au, (ii) TiO2 with embedded Au nanoparticles in a sandwichlike fashion, TiO2/Au/TiO2, and (iii) TiO2 with embedded and decorated Au nanoparticles, TiO2/Au/TiO2/Au. The TiO2/Au composite resulted in the highest photocurrent response under UV irradiation and in a broadening of the photocurrent response to the visible region, although with successive testing a decrease in the photocurrent response was observed. The photoresponse of the buried Au nanoparticles, TiO2/Au/TiO2, was slightly lower compared to Au decorating the TiO2 electrosynthesized surface, TiO2/Au, but significantly higher than pristine electrosynthesized TiO2. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3246617] All rights reserved.