Our energy research is focused on the synthesis, detailed characterization and activity studies of bimetallic nanoparticles (NPs) for use in catalytic transformations in energy systems. We develop new catalytic materials for use as CO-tolerant hydrogen electrocatalysts for proton exchange membrane fuel cells (PEMFCs), oxygen activation electrocatalysts for PEMFC cathodes, PROX catalysts and de-NOx catalysts for emissions control in internal combustion engines. A central theme in our research is understanding the relationship between the activity of a nanoparticle catalyst with its composition, structure and architecture. We have developed synthetic methods to prepare series of well-characterized bimetallic NPs in which we can control the architecture to elicit different activities. For example, AuPt NPs can be prepared as alloys, core-shell structures, contact aggregates or monometallic mixtures that each have unique catalytic properties. Our catalysts are thoroughly characterized by employing the sophisticated analytical tools available at UMD; namely, X-ray diffraction, high resolution TEM, phase mapping, X-ray photoelectron spectroscopy, in situ Raman spectroscopy, probe IR experiments and TGA. In addition, full catalytic evaluations of our systems are conducted by performing temperature programmed reactions (TPR) of supported NP catalysts in temperature-controlled fixed bed reactors. Products are monitored through continuous mass spectrometric sampling and catalysts are evaluated for activity, selectivity and stability under a variety of conditions.
A second focus of our energy research is the study of the basic chemistry occurring at the anode-gas interface of a solid oxide fuel cell (SOFC). We investigate the structure and properties of carbon deposits from the use of hydrocarbon fuels in various configurations of SOFCs. In addition, we probe the mechanistic steps of fuel oxidation, diffusion, charge transfer and other transformations by way of electrochemical impedance spectroscopy (EIS), voltammetry, isotopic labeling studies and spectroscopic evaluation.