Atish Parekh

Graduate Research Assistant

Co-advised by Professors Fabio Ribeiro and W. Nicholas Delgass


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Background

Education

IIT Bombay , B.Tech. Chemical Engineering (2010)
Purdue University, M.S. Chemical Engineering (2013)

Experience

Awards

  • 3rd place poster award, Annual Chemical Engineering GSO Symposium (2014)
  • Outstanding oral presentation award, Michigan Catalysis Society, Spring Symposium (2014)
  • Goddard Fellowship (2010)
  • CBSE Merit Scholarship for securing an All India Rank of 23 in the All India Engineering Entrance Exam (2006)

About Me

I am from Mumbai, India. I am very passionate about music and an active member of Purdue Taal, Purdue University's one and only Indian-American a cappella group. I play the keyboard/piano for the Indian Classical Music Association of Purdue (ICMAP). Apart from music I also enjoy traveling, backpacking, dancing and volunteering for community activities.

Project Description

Cu-exchanged zeolites, especially the small pore CHA structure, are promising catalysts for NOx removal from automotive exhausts via the ammonia selective catalytic reduction (NH3 SCR) reduction, while NO oxidation is proposed to play an important role in the SCR reaction. The goal of my thesis is to understand the nature of the active metal sites and identify key intermediates for the ammonia selective catalytic reduction (NH3 SCR) and NO oxidation reactions. Catalysts are synthesized in-house and characterized using XRD, BET surface area/micropore volume, acid site measurements, and atomic absorption spectroscopy to ensure that we have the correct structure. A combination of techniques such as kinetics, FTIR and X-ray absorption spectroscopy are used to elucidate reaction pathways.

A state-of-the-art operando FTIR-MS setup was built and commissioned as part of this work. One reactant gas in the feed is replaced with its corresponding isotope at steady state. The isotope label manifests itself in the FTIR as a shift in the vibrational frequencies of specific vibrations, while it can simultaneously be followed in the effluent gas using the mass spectrometer. These fast switching steady state isotope transient kinetic experiments allow us to identify, quantify and calculate the average residence time for the true reactive intermediates on the catalyst surface, and differentiate them from spectator species, thereby elucidating the reaction mechanism.

X-ray absorption experiments on the other hand allow us to probe the state of the exchanged Cu ions in the zeolite under its operating conditions. These experiments, performed at the Advanced Photon Source at Argonne National Laboratory give us quantitative information about the fraction of different oxidation states of Cu present at steady state (whether it exists as Cu(0), Cu(I) or Cu(II)) as well as its coordination environment. All these experiments are performed under operando conditions to ensure that we get relevant spectroscopic information about the catalyst while it is in normal operation.

Finally, this is a collaborative effort with Prof. William F. Schneider's group at the University of Notre Dame. They model the reaction pathways and obtain information about kinetic barriers via first principles DFT simulations, reconciling experimental observations and theoretical predictions.

Publications