Mechanisms of Electrocatalytic Kinetics of Oxidation of Hydrocarbons on Solid-Oxide Electrolyte-Electrode Surfaces. Final Report

摘要

This report presents highlights of the results obtained to date on an ongoing investigation of the electrocatalytic mechanisms involved in the anodic oxidation of selected hydrocarbons derivable from coal gas, and the cathodic reduction of O sub 2 in a fuel cell employing Sc sub 2 O sub 3 -or Y sub 2 O sub 3 -stabilized ZrO sub 2 . The particular focus of the work has been to perform definitive experiments to show that the solid electrolyte plays an important role in electrocatalysis compared to the porous metallic electrode. It has been observed that great enhancement in reaction-rates and current drawn at a given overpotential occurs when the electrolyte is blackened by electrolysis, forming a stable suboxide of zirconia, ZrO/sub 2-x/. Simple potentiometric measurements with pure H sub 2 , CO, CH sub 4 , CH sub 3 OH and C sub 2 H sub 5 OH, as the fuel and air oxidant have been made on both the ZrO sub 2 -Sc sub 2 O sub 3 system in both the unblackened and blackened state. The general kinetic information resulting from this study is being used for optimal modeling and design of practical tubular shaped solid-electrolyte fuel cells employing air and hydrocarbons. A laboratory scale tubular electrochemical reactor has been constructed to provide experimental data of value in modeling. (ERA citation 09:020351)