N.J. Ray, E.G. Karpov
University of Illinois at Chicago,
Keywords: mesoporous zirconia, electrolytic oxidation, reaction current, oxyhydrogen, hydrogen spillover
Summary:We advocate on the existence of a large class of surface-driven functional nanocomposite mesoporous systems adept at converting surface-released chemical energy into a stationary reaction current when subjected to oxyhydrogen conditions at room temperature. Recently, there has been a large interest and amount of work studying thermionic currents and chemicurrents generated by Pt/TiO2 systems under exposure to oxyhydrogen environments; we now report on mesoporous ZrO2 (synthesized via plasma electrolytic oxidation) with Pt deposition exhibiting similar properties. Through the adjustment of anodization parameters, ZrO2 pore diameter and pore density can be controlled. Substrates oxidized at 2.2 mA/cm^2 result in a fractional surface area of 0.49% pores, while a fractional surface area of 3.35% pores corresponds to an anodization current of 55 mA/cm^2. Increases in pore density leads to reaction current enhancement, as well as an initially heightened H2 sensitivity. The low current densities make this a very cost-effective technique to produce electrolyte-free nanosystems able to generate electrical power under oxyhydrogen environments at room temperature.