title: A Stationary Reaction Current Effect in Mesoporous Pt/ZrO2 System Under H2/O2 Environment.
abstract: There have been many works analyzing thermionic currents and chemicurrents generated on various electrolyte-free metal/semiconductor nanostructures. More recently, the chemicurrent phenomenon was reported for mesoporous Pt/semiconductor systems adept at converting surface-released chemical energy into a stationary electrical signal at room-temperature conditions. The present work points out the existence of an entire class of such surface-driven functional nanosystems. Here, the reaction current generation of Pt/ZrO2 systems was studied at room temperature under exposure to oxyhydrogen environments for mesoporous zirconia; this nanostructure was capable of the continuous oxidation of hydrogen, producing a long-standing stationary current. Synthesis parameters during the anodization process were manipulated to control sample pore density and the average pore diameter. Deposited via wide-angle PVD sputtering, the Pt phase forms an electrically continuous topographical nanomesh layer, and thus the Pt/ZrO2/gas interface is regulated through the manipulation of zirconia porosity. We observed reaction current enhancements with increasing porosity due to the lengthening of the Pt/ZrO2 interface. The most porous sample was significantly more sensitive to initial hydrogen additions, pointing toward the spillover of positive ionic charge across the Pt/ZrO2 interface as the origin of the observed electromotive force.
authors.affiliation: University of Illinois at Chicago , Chicago, Illinois 60607, United States.
authors.forename: Nathan J
authors.initials: NJ
authors.lastname: Ray
authors.affiliation: University of Illinois at Chicago , Chicago, Illinois 60607, United States.
authors.forename: Mohammad A
authors.initials: MA
authors.lastname: Hashemian
authors.affiliation: University of Illinois at Chicago , Chicago, Illinois 60607, United States.
authors.forename: Eduard G
authors.initials: EG
authors.lastname: Karpov
keywords: electrolytic oxidation; hydrogen spillover; mesoporous zirconia; oxyhydrogen; reaction current