Tuning the electronic structure of titanium oxide support to enhance the electrochemical activity of platinum nanoparticles

Two times higher activity and three times higher stability in methanol oxidation reaction, a 0.12 V negative shift of the CO oxidation peak potential, and a 0.07 V positive shift of the oxygen reaction potential compared to Pt nanoparticles on pristine TiO₂ support were achieved by tuning the electronic structure of the titanium oxide support of Pt nanoparticle catalysts. This was accomplished by adding oxygen vacancies or doping with fluorine. Experimental trends are interpreted in the context of an electronic structure model, showing an improvement in electrochemical activity when the Fermi level of the support material in Pt/TiO_x systems is close to the Pt Fermi level and the redox potential of the reaction. The present approach provides guidance for the selection of the support material of Pt/TiO_x systems and may be applied to other metal-oxide support materials, thus having direct implications in the design and optimization of fuel cell catalyst supports.