We look for the fundamental properties that govern electrochemical behavior: reactivity, selectivity, conductivity and mass transport.
Carbon materials are fascinating electrocatalysts. In the alkaline oxygen reduction reaction (ORR), some doped carbons compete successfully with the best platinum catalysts. Their high porosity exposes many active sites, yet creates a tortuous pathway through which reagents (O2) and products (OH–) cannot diffuse fast enough, bubbles are slow to remove, and surface wetting may be difficult.
Hierarchical porosity is hard to produce. The ‘brute force’ method involves multi-step templating, yielding well-designed yet expensive structures. At the other extreme, the ‘serendipitous’ approach relies on pyrolyzing various biomass types (from bacteria to mammals), occasionally stumbling on excellent electrocatalysts. We seek the golden path: starting from simple and well-crafted precursors and/or templates, and driving towards full control of structure, composition, and activity.
To design hierarchical porosity, we explore concepts such as self-templating, tunable ZnO macro-templating, phase-separation of polymers, and more. We are particularly interested in understanding (quantitatively) the role of pore connectivity in electrocatalysis.