Novel Materials and Characterization Methods for Electrocatalysis
LaboratorySandia National Laboratories (SNL)
Capability ExpertMark Allendorf, Rob Kolasinski, Vitalie Stavila, Alec Talin
Node Readiness Category3: High-Temperature Electrolysis (HTE)
3: Low-Temperature Electrolysis (LTE)
3: Photoelectrochemical (PEC)
3: Solar Thermochemical (STCH)
Our electrocatalyst capabilities encompass novel materials and synthetic methods, as well as a number of specialized characterization tools. Novel catalyst materials and synthetic routes: (a) nanoporous Metal-Organic Frameworks (MOFs) that are thermally and electrochemically stable, can be infiltrated with various catalytic species to promote the oxygen reduction and hydrogen oxidation reactions, and can be either conducting or insulating, depending on MOF structure and pore chemistry; (b) nanoporous noble metals with high surface area and unique catalytic activity that can be synthesized on gram scales; and (c) the Sandia-invented Atomic-Layer Electroless Deposition method to deposit precise amounts of noble metals onto catalysts under mild conditions. (2) Unique catalyst characterization methods that complement our standard electrochemical characterization capabilities, such as a low-energy ion scattering (LEIS) instrument optimized for probing hydrogen and oxygen surface reactions and scanning electrochemical Raman microscopy (SERM) for in operando catalyst activity characterization with high spatial and spectral resolution. SNL also has synthesis, characterization, and computational capabilities needed to design novel electrocatalysts, characterize their properties, create membranes and membrane electrode assemblies (MEAs), and evaluate electrochemical performance. Quartz Crystal Microbalance (QCM) systems are available to monitor growth of MOF and metal films on electrode materials in-situ. Infiltration methods are available to introduce guest species (molecules,1 metal clusters,4 or nanoparticles2) within MOF pores to create materials that can catalytically activate the hydrogen molecule. Our MOF catalytic platforms also have tunable pore sizes (1 – 10 nm) and can incorporate catalytically active centers, such as open metal sites, that confine reactants and consumable reagents such as hydrogen peroxide to promote high conversion and efficient reagent use. The SERM platform employs a mRaman system to allow local electrochemical activity to be correlated with chemical composition in solution.3
Using our QCM instrumentation we can monitor with sub-monolayer sensitivity processes occurring on electrode surfaces in situ. Combining this with SERM allows electrochemical activity and composition to be measured with sub-micron spatial resolution.
SNL is an internationally recognized leader in the development of MOFs for practical applications, with several MOF-related "firsts," including integration with MEMS devices, measurement of mechanical properties, catalytic nanoreactors for hydrogen storage, and luminescent MOFs for radiation detection. Our expertise in MOF thin film and membrane fabrication will further the development of high performance and low-cost MEAs. Our scalable synthetic methods for nanoporous noble metals contrast with many literature techniques that yield on the order of a liter of hazardous waste per milligram of catalyst formed, but also allow for economical use of noble metals through precise deposition.
The capability is available to staff, students, and visitors of SNL-CA in Livermore, CA.
SEPCM (b,d) and SECM (c,e) mapping of H2 evolution in a Pt/SiO2/Si photocathode. The laser source is now coupled to Raman spectrometer for simultaneous vibrational spectroscopic analysis.
1. A.A. Talin, A. Centrone, A.C. Ford, M.E. Foster, V. Stavila, P. Haney, R.A. Kinney, V. Szalai, F. El Gabaly, H.P. Yoon, F. Leonard, M.D. Allendorf, Science, 2014, 343, 66–69.
2. V. Stavila, R.K. Bhakta, T.M. Alam, E.H. Majzoub, M.D. Allendorf, ACS Nano, 2012, 6, 9807-9817.
3. D. V. Esposito, I. Levin, T. P. Moffat, and A. A. Talin, "Hydrogen Evolution at Si based Metal-Insulator-Semiconductor Photoelectrodes Enhanced by Inversion Channel Charge Collection and Hydrogen Spillover", Nature Materials, 2013, 12, 562-568