Fundamental studies on copper zeolites for catalytic NO x abatement

239 Pages·2016·11.92 MB·English

by  Anuj Arun Verma

Purdue University
Purdue e-Pubs
Open Access Dissertations Theses and Dissertations
Summer 2014
Fundamental studies on copper zeolites for
catalytic NO x abatement
Anuj Arun Verma
Purdue University
Follow this and additional works at:https://docs.lib.purdue.edu/open_access_dissertations
Part of theChemical Engineering Commons, and thePhysical Chemistry Commons
Recommended Citation
Verma, Anuj Arun, "Fundamental studies on copper zeolites for catalytic NO x abatement" (2014).Open Access Dissertations. 378.
https://docs.lib.purdue.edu/open_access_dissertations/378
This document has been made available through Purdue e-Pubs, a service of the Purdue University Libraries. Please contact [email protected] for
additional information.
30
0814
PURDUE UNIVERSITY
GRADUATE SCHOOL
Thesis/Dissertation Acceptance
Anuj Arun Verma
FundamentalStudiesonCopperZeolitesForCatalyticNOxabatement.
Doctor ofPhilosophy
FabioH.Ribeiro JoshuaRatts
W.NicholasDelgass
AlekseyYezerets
StephenBeaudoin
FabioH.Ribeiro
JohnMorgan 08/20/2014
Department

i
FUNDAMENTAL STUDIES ON COPPER ZEOLITES FOR CATALYTIC NOX
ABATEMENT
A Dissertation
Submitted to the Faculty
of
Purdue University
by
Anuj Arun Verma
In Partial Fulfillment of the
Requirements for the Degree
of
Doctor of Philosophy
December 2014

Purdue University
West Lafayette, Indiana
ii

To my parents, Ashish Dada, Poonam Bhabhi, and Sneha!
iii
ACKNOWLEDGEMENTS
Remain calm during your successes for that calmness will help you overcome your
failures. – Adapted from the Bhagwad Gita.

As this maxim goes, my journey leading up to PhD has tasted many successes and
failures and this proverb has helped me immensely. This journey has enabled me to be a
much wiser person than I was when I first arrived in Purdue University four years ago (12
August, 2010). This transformation, however, would have been impossible without me
meeting certain people who I would like to acknowledge below.

First and Foremost, I would like to thank Professor Fabio Ribeiro, my advisor. He has
stood behind me like a rock during my ups and downs in my PhD life. I especially admire
his experimental abilities and his emphasis of data reproducibility. If a data-set passes the
‘Fabio’ test, then rest assured, it will be reproducible in other laboratories. I am also
thankful to Fabio for granting more independence in the DeNOx project than other
projects in the catalysis group. This has enabled us to ‘own’ the project and generate new
ideas and hypotheses. Moreover, I would like to apologize to Fabio for pursuing a career
in industry rather than in academia. I would also like to thank Professor Nick Delgass for
teaching me concepts of catalysis and spectroscopy. His unique ability to process data-
sets and provide new information has been invaluable in my career. Moreover, his

emphasis on developing a ‘mosaic’ or a vision of understanding in any field is one of his
teachings that I hope to apply in my future career.

I would like to thank Dr. Aleksey Yezerets for his industrial inputs given to the DeNOx
group. His ability to gather seemingly disparate concepts and apply it in industrially
iv
relevant scenarios is something I hope to implement in my own career. I would also like
to acknowledge his DeNOx team at Cummins Inc. for being very helpful in all the
wonderful meetings we had. I would also like to acknowledge Dr. Joshua Ratts for
providing me with valuable advice in my research and agreeing to be in my PhD
committee. Professor Stephen Beaudoin is gratefully acknowledged for agreeing to take
part in my PhD committee. I would also like to thank Dr. Jeffrey Miller from whom I
learnt about the intricacies of catalyst synthesis and X-ray absorption spectroscopy. Big
thanks to my collaborators, Professor William Schneider, Trunojoyo Anggara, and
Christopher Paolucci. I have always viewed you guys (Trunojoyo and Chris) as internal
members of the NOx group and Prof. Schneider as my third boss. I still maintain that
doing computational work is tougher than doing experiments and you people make that
look so easy and elegant. I also want to thank Dr. Raj Gounder for teaching me the art of
zeolite synthesis and characterization.

Big thanks to Dr. Yury Zvinevich. He taught me how to build complex equipments and
more importantly, how to maintain the same. His teachings will be remembered in my
professional life. I also want to acknowledge Robb and Dr. Mike Everly from the Amy
Instrument facility in Chemistry department, Purdue University. They implemented the
labview program which enabled me to get data in record time.

I thank all my colleagues with whom I worked together in the field of catalysis. In

particular, Jun Wang, Atish Parekh, Shane Bates, and Vincent Kispersky are
acknowledged. Other members in the catalysis group, Dhairya, Harsha, Vinod, Paul,
Shankali, Han-ting, Zhenglong, Jamie, Tej, Mike, Amir, Viktor, and Yanran are also
acknowledged. I also wish Arthur Shih, Jonatan Albarracin, and John Di Iorio the very
best as the new members of the DeNOx group. I think Fabio and Raj could not have
asked for better students. I also acknowledge Austin Tackaberry for help in zeolite
synthesis.
v
I am grateful to all my friends who kept me sane during my PhD study. In particular, a
very big thanks to Piyush, Gautham, Ankit, Nitin, Sambit, Raghu, Krishna, and Nitish:
The ECE gang. While the ChemE gang included Dhairya, Harsha, Mayank, Ranjita,
Shenvi, Dude, Krishnaraj, Karthikeyan, Joglekar, Ravi, Pritish, Sumeet, Tej, and
Anuradha.

Last but not the least; I would like to thank my parents, Asha and Arun, and Ashish and
Poonam for encouraging me to make my own decisions in life. It is only because of your
patience that I am here. My sincere apologies for not being in contact as frequently as
desired but your understanding is proof enough that you would do anything to see me
healthy and happy. Finally, a very big thanks goes to Sneha, who taught me that there is
life outside of research and who has patiently been by my side through all these years.
vi
TABLE OF CONTENTS
Page
LIST OF TABLES ............................................................................................................. ix
LIST OF FIGURES ........................................................................................................... xi
ABSTRACT ............................................................................................................. xx
CHAPTER 1. INTRODUCTION ................................................................................. 1
1.1 Introduction ................................................................................................1
1.2 Cu-Zeolite As a Catalyst for standard SCR ...............................................3
1.3 Thesis Overview ........................................................................................8
CHAPTER 2. A KINETIC AND SPECTROSCOPIC STUDY OF STANDARD SCR
ON COPPER EXCHANGED SSZ-13 ............................................................................. 10
2.1 Abstract ....................................................................................................10
2.2 Introduction ..............................................................................................11
2.3 Experimental Methods .............................................................................13
2.3.1 Cu-SSZ-13 Synthesis and Characterization ..................................... 13
2.3.2 Kinetic Data Collection .................................................................... 13
2.3.3 X-Ray Absorption Measurements .................................................... 15
2.3.4 Operando XAS Experimental Setup ................................................ 16
2.3.5 UV-Visible Near IR Measurements ................................................. 17
2.3.6 Density Functional Theory Calculations .......................................... 17
2.4 Results ......................................................................................................18
2.4.1 Kinetics of standard SCR on Cu-SSZ-13 ......................................... 18
2.4.2 Brønsted Acid Site Counting ............................................................ 21
2.4.3 Active Cu Characterization .............................................................. 23
2.5 Discussion ................................................................................................29
2.5.1 Identification and Location of the Active Cu species ...................... 29
2.5.2 Transition to Other Cu species after Cu:Al = 0.2 ............................. 31
2.5.3 Choice of Brønsted Acid site Measurement Technique ................... 32

2.5.4 The Role of Residual Brønsted Acid Sites ....................................... 33
2.5.5 The Importance of Cu:Al = 0.2 ........................................................ 35
2.6 Conclusions ..............................................................................................35
2.7 Acknowledgements ..................................................................................36
CHAPTER 3. KINETICS OF OXIDATION OF NITRIC OXIDE OVER COPPER
EXCHANGED SSZ-13 .................................................................................................... 38
3.1 Abstract ....................................................................................................38
3.2 Introduction ..............................................................................................39
3.2 Experimental Methods .............................................................................41
vii
Page
3.2.1 Synthesis and Characterization of Cu-SSZ-13 ................................. 41
3.2.2 Kinetic Measurements ...................................................................... 43
3.2.3 X-ray Absorption Measurements ..................................................... 44
3.2.4 Ex-situ Ultraviolet Visible Near Infra-red (UV-Vis-NIR)
Spectroscopy .......................................................................................................... 45
3.3 Computational Methods ...........................................................................45
3.4 Results ......................................................................................................47
3.4.1 Dry NO Oxidation Kinetics on Varying Cu:Al Ratios over
Cu-SSZ-13 .......................................................................................................... 47
3.4.2 Ex-Situ XANES and UV-Vis-NIR Spectroscopy on Hydrated Cu-
SSZ-13 Catalysts under Ambient Conditions ........................................................... 51
3.4.3 XANES analysis of Cu-SSZ-13 Catalysts under In-Situ NO
Oxidation Condition .................................................................................................. 55
3.4.4 Computational Cu Site Models ........................................................ 58
3.5 Discussion ................................................................................................66
3.5.1 The Active Cu Ion Configuration for Dry NO Oxidation on
Cu-SSZ-13 .......................................................................................................... 66
3.5.2 On the Dominant Cu Ion Configuration Below Cu:Al Ratio of 0.2 68
3.5.3 On the Difference In The Rates of NO Oxidation Between Isolated
Cu(II) Ions and Cu O Species ................................................................................. 70
x y
3.6 Conclusions ..............................................................................................71
3.7 Acknowledgements ..................................................................................72
CHAPTER 4. ISOLATION OF THE COPPER REDOX STEPS IN STANDARD
SCR ON COPPER EXCHANGED SSZ-13 ..................................................................... 73
4.1 Abstract ....................................................................................................73
4.2 Introduction ..............................................................................................73
4.3 Results and Discussion .............................................................................76
4.4 Conclusions ..............................................................................................85
4.5 Acknowledgements ..................................................................................86
CHAPTER 5. PREVENTION OF FALSIFICATION OF REACTION KINETICS

BY PRODUCT INHIBITION .......................................................................................... 87
5.1 Abstract ....................................................................................................87
5.2 Introduction ..............................................................................................87
5.3 Experimental Methods .............................................................................89
5.3.1 Catalyst Preparation ......................................................................... 89
5.3.2 Catalytic Testing .............................................................................. 89
5.4 Results ......................................................................................................90
5.4.1 Kinetic Experiments in Presence of NO in the Feed Stream .......... 90
2
5.4.2 Kinetic Experiments in Absence of NO in the Feed Stream .......... 93
2
5.5 Discussion ................................................................................................95
5.5.1 The Problem: Ignoring Inhibition Leads to Substantial Errors ........ 96
5.5.2 The Solution: Add Product to the Feed ............................................ 99
5.6 Conclusions ............................................................................................104
CHAPTER 6. CONCLUSIONS ............................................................................... 105