Conceptual illustration of an electrochemical reactor where oxygen ions are transported through the electrolyte, are oxidized at the anode, and then participate in surface reactions that reform hydrocarbon fuel.

Transitioning to a hydrogen fuel-based economy will require innovative means of hydrogen production from fossil fuels. One option is steam reforming, but current processes are not efficient enough to deliver H₂ for transportation at competitive market prices. Sandia researchers are developing a novel solid-oxide fuel-cell reactor for the conversion of CH₄ and other fossil fuels to H₂ that will increase process efficiency by direct cogeneration of electricity during fuel reforming.

A fuel cell generates electricity from the oxidation of hydrogen or hydrocarbon fuels to water and carbon dioxide. An advanced fuel-cell reactor is designed to control the oxidation reactions to produce hydrogen or other valuable oxygenated hydrocarbons, in addition to electricity.

This research leverages Sandia expertise in ceramic materials processing, catalyst design, and reaction engineering to rapidly prototype and evaluate ultra-thin membrane structures functionalized for selective oxidation of hydrocarbons. We are using advanced laser diagnostics, mass spectrometry, and impedance spectroscopy to gain insight into pertinent surface-mediated processes such that optimized reactor configurations may be realized. The challenge is to discover anode catalysts and electrolyte materials, as well as reactor operating conditions that optimize reactant conversion, product selectivity, and power output.

Photograph of jet-stirred reactor operating at high temperature under selective partial oxidation of methane to produce hydrogen. Windows allow for optical access to reacting surface, which enables surface Raman measurements at temperature.

Our goal is to synthesize and evaluate novel, low-temperature ion-conducting membranes catalytically activated for the desired chemistry. Membrane performance is carefully scrutinized by identifying prominent anode adsorbates, interrogating the kinetics of oxygen transport, resolving differences between the reactivity of lattice and adsorbed forms of oxygen, as well as evaluating the relative effects of cell bias voltage and current density on performance.

Simultaneous measurement of gas species and electrochemical properties during partial oxidation of methane (CH₄). Variability in cell current is evidence of system responding to net oxidizing or reducing conditions at the anode under a fixed potential.

Contact:
Tony McDaniel
amcdani@sandia.gov
(925) 294-1440