Seminar

Improving the properties of electrodes and electrocatalysts is critical to both understanding and making step changes in the performance and durability of all electrochemical devices, including batteries, capacitors, fuel cells and electrolysis cells. In most cases, the electrodes must be porous (high surface area), conducting (often both ionically and electronically), have high catalytic activity, and must also be as durable aspossible, especially considering the often aggressive oxidation/reduction conditions encountered during device operation. As part of this quest for high performance electrode materials, we have developed a promising class of perovskite metal oxide (ceramic) electrocatalysts (La0.3M0.7Fe0.7Cr0.3O3-δ (M = Sr,Ca, LMFCr) for use in high temperature all-solid-state fuel cells and electrolysis cells. LMCr is highly active and durable during reactions of oxygen, hydrogen, steam, CO2, CO and even in low ppm H2S environments, thus opening the door to symmetrical, reversible solid oxide cells. These can serve to store energy by CO2 and/or water splitting to produce CO and/or H2, which are then available for use in electricity generation when needed via the reverse reactions. In another direction, we have developed a novel family of nano-templated carbon materials, with carbon being a ubiquitous material that is used in many low temperature electrochemical systems. However, most carbons are microporous (their internal surface area cannot be easily used) and are in powder form, thus requiring binders, leading to mass transport limitations and blockage of catalytic sites. To overcome these problems, we have developed a family of ordered mesoporous carbon powders as well as paradigm-shifting binderless, self- supported, nanoporous carbon scaffolds (NCS). Pt nanoparticles loaded into the NCS have given
world-leading oxygen reduction kinetics in PEM fuel cell membrane-electrode-assemblies, while heteroatom+single metal atom doping of both the powders and scaffolds result in highly selective and active CO2 and/or water reduction to produce H2. The NCS sheets have also been employed as flow-through electrodes in redox-flow batteries and as a model material for the study of imbibition of fuids into nanoporous structures.