Heterogeneous catalysis is an integral component of many technologies that drive our chemical and energy industries. We are an experimental research group that studies the fundamentals and applications of heterogeneous catalysis and the targeted synthesis of inorganic solids and molecular sieves. We combine approaches in materials synthesis, characterization, and kinetic and mechanistic studies to probe the site requirements, reactive intermediates and elementary steps that constitute reaction mechanisms. We aim to develop structure-function relations that predict how reactant and catalyst structures influence reactivity and selectivity, in order to inform catalyst design and selection for new and existing catalytic processes.

Our current research interests fall within the following areas:
(i) catalytic routes and materials that enable the conversion of petroleum- and natural gas-derived hydrocarbons to transportation fuels and chemicals
(ii) catalyst design for selective reactions of multifunctional and polyfunctional molecules, such as those derived from renewable biomass, in liquid and gaseous phases
(iii) selective catalytic reduction of NOx (x = 1, 2) compounds with ammonia for pollution abatement in lean-burn engine emissions

We also focus on investigating microporous and mesoporous materials, zeolites, and molecular sieves, which are prevalent in the petrochemical refining and chemical industries. These crystalline oxides contain catalytically active sites confined within ordered void spaces (channels, cages, pockets) of molecular dimension (typically <2 nm). The properties of both the active sites and the confining environments can strongly influence catalytic rates and selectivities. In certain contexts, synthetic molecular sieves show catalytic reactivity and specificity reminiscent of that displayed by biological enzymes. One long-term goal of our research program is to understand fundamentally why and when synthetic materials exhibit such remarkable catalytic behavior.

We are a part of the Purdue Catalysis Center, which fosters interaction among faculty and students in catalysis research groups by collaborating on research projects, sharing resources and facilities, and holding weekly joint group meetings.

"Influence of Framework Al Density in Chabazite Zeolites on Copper Ion Mobility and Reactivity During NOx Selective Catalytic Reduction with NH3" S. H. Krishna, A. Goswami, Y. Wang, C. B. Jones, D. P. Dean, J. T. Miller, W. F. Schneider, R. Gounder, Nature Catalysis, 6, 276-285, (2023).

"Influence of Bronsted-Acid Site Density on Reaction-Diffusion Phenomena that Govern Propene Oligomerization Rate and Selectivity in MFI Zeolites" E. E. Bickel, S. Lee, R. Gounder, ACS Catalysis, 13, 1257-1269, (2023).

"Hydrocarbon Products Occluded within Zeolite Micropores Impose Transport Barriers that Regulate Br??nsted Acid-Catalyzed Propene Oligomerization" E. E. Bickel, R. Gounder, JACS Au, 2, 2285-2295, (2022).

"Dynamic Interconversion of Metal Active Site Ensembles in Zeolite Catalysis" S. H. Krishna, C. B. Jones, R. Gounder, Annual Review of Chemical and Biomolecular Engineering, 12, 115-136, (2021).

"Effects of Br??nsted Acid Site Proximity in Chabazite Zeolites on OH Infrared Spectra and Protolytic Propane Cracking Kinetics" P. M. Kester, J. T. Crum, S. Li, W. F. Schneider, R. Gounder, Journal of Catalysis, 395, 210-226, (2021).

"Solvation and Mobilization of Copper Active Sites in Zeolites by Ammonia: Consequences for the Catalytic Reduction of Nitrogen Oxides" C. Paolucci, J. R. Di Iorio, W. F. Schneider, R. Gounder, Accounts of Chemical Research, 52, 1881-1892, (2020).

"Cooperative and Competitive Occlusion of Organic and Inorganic Structure Directing Agents within Chabazite Zeolites Influences Their Aluminum Arrangement" J. R. Di Iorio, S. Li, C. B. Jones, C. T. Nimlos, Y. Wang, E. Kunkes, V. Vattipalli, S. Prasad, A. Moini, W. F. Schneider, R. Gounder, Journal of the American Chemical Society, 142, 4807-4819, (2020).

"Effects of Dioxygen Pressure on Rates of NOx Selective Catalytic Reduction with NH3 on Cu-CHA Zeolites" C. B. Jones, I. Khurana, S. H. Krishna, A. J. Shih, W. N. Delgass, J. T. Miller, F. H. Ribeiro, W. F. Schneider, R. Gounder", Journal of Catalysis, 389, 140-149, (2020).

"Parallel Alkane Dehydrogenation Routes on Bronsted Acid and Reaction-Derived Carbonaceous Active Sites in Zeolites" P. M. Kester, E. Iglesia, R. Gounder, Journal of Physical Chemistry C, 124, 15839-15855, (2020).

"Structure and Solvation of Confined Water and Water-Ethanol Clusters within Microporous Bronsted Acids and their Effects on Ethanol Dehydration Catalysis" J. S. Bates, B. C. Bukowski, J. Greeley, R. Gounder, Chemical Science, 11 7102-7122, (2020).

"Rigid Arrangements of Ionic Charge in Zeolite Frameworks Conferred by Specific Al Distributions Preferentially Stabilize Alkanol Dehydration Transition States" A. J. Hoffman, J. S. Bates, J. R. Di Iorio, S. V. Nystrom, C. T. Nimlos, R. Gounder, D. Hibbitts, Angewandte Chemie International Edition, 59, 18686-18694, (2020).

"Dynamic Multinuclear Sites Formed by Mobilized Copper Ions in NOx Selective Catalytic Reduction" C. Paolucci, I. Khurana, A. A. Parekh, S. Li, A. J. Shih, H. Li, J. R. Di Iorio, J. D. Albarracin-Caballero, A. Yezerets, J. T. Miller, W. N. Delgass, F. H. Ribeiro, W. F. Schneider, R. Gounder, Science, 357, 898-903, (2017).

"Introducing Catalytic Diversity into Single-Site Chabazite Zeolites of Fixed Composition via Synthetic Control of Active Site Proximity" J. R. Di Iorio, C. T. Nimlos, R. Gounder, ACS Catalysis, 7, 6663-6674, (2017).