Kinetics and Transport - ElectroCat Consortium

Laboratory:	National Renewable Energy Laboratory
Capability Expert:	Kenneth (K.C.) Neyerlin
Capability Details:
*Title:*	Operando differential cell measurements of electrochemical kinetics and transport
*Class:*	Characterization
*Description:*	This capability takes advantage of fully automated testing equipment with a variety of unique aspects to extract PGM-free electrochemical kinetic data via in-operando testing in a differential cell configuration. Transport resistance measurements (e.g. limiting current) are also available using a variety of probe gases and diluents.
*Unique Aspects:*	1) Measurements performed in a differential cell at high stoichiometry, 2) Ability to measure performance from sub-ambient partial oxygen pressures (~15kPa pO₂) to 350 kPa pO₂ while maintaining a pure oxygen atmosphere (i.e., no gas phase transport resistance), 3) On demand automated flow mixing of O₂, N₂, CO, He, and Ar for transport diagnostics (not limited to pre-mixed bottled gases), and 4) completely automated gas switching, flow, temperature, RH, pressure, current/voltage control and cyclic voltammetry.
*Availability:*	This capability has limited availability due to equipment use.
*References:*	Neyerlin, K.C., et al. Journal of The Electrochemical Society 153.10 (2006): A1955-A1963. Subramanian, N.P., et al. Journal of The Electrochemical Society 159.5 (2012): B531-B540. Greszler, et al. Journal of The Electrochemical Society 159.12(2012): F831-F840.
*Benefit:*	The existing capability provides ElectroCat with the ability to thoroughly characterize the electrochemical kinetics of PGM-free materials. This will allow for the extraction of fundamental parameters such as exchange current density, activation energy, and reaction order, which in turn will give insight into the reaction mechanisms that govern various PGM-free electrocatalysts. Transport resistance measurements can elucidate the pressure-dependent and -independent resistances, isolating contributions from various electrode design parameters that are unique to PGM-free electrocatalysts.