Computational catalysis and materials design group

Rangarajan research group

We are a group of computational chemical engineers in the Department of Chemical & Biomolecular Engineering at Lehigh University.

We use computational techniques to study two categories of problems: (i) elucidating the mechanism of catalytic reactions, and (ii) designing organic and inorganic materials. Our problems are inspired by the opportunities and challenges in converting unconventional carbon sources (biomass, carbon dioxide, shale gas, and even waste plastics) to energy carriers and chemicals. Our problems are characterized by complex chemistries.  

To study these problems, we develop and employ a unique collection of tools spanning computation chemistry, process systems engineering, and machine learning. This includes ab initio methods (e.g. density functional theory, or DFT), cheminformatics,  optimization, neural networks and Gaussian processes, multifidelity modeling, design of experiments, global sensitivity, sparse modeling, and Bayesian statistics. We have developed tools to: (i) construct and analyze complex reaction networks and identify organic synthesis pathways and (ii) formulate and solve microkinetic models of catalytic systems. We routinely use quantum chemistry tools such as Vienna Ab initio Simulation Package (VASP), Quantum Espresso, and Gaussian to study catalytic reactions. 

We work closely with several groups within and outside Lehigh. Specifically, we work with machine learning and optimization experts to adapt cutting edge mathematical techniques for our applications and collaborate with operando spectroscopy, kinetics, and synthesis groups to provide a complementary computational angle to problems in catalysis and materials design.  Our work is (has been) supported by NSF, DOE, ACS, Lehigh university internal grants, the commonwealth of PA, and the industry. 

Group news

Jan 2023

• Srinivas will teach a machine learning/data science elective this spring. The goal of this course is to introduce chemical engineering students (and those of allied disciplines) to the world of data-driven modeling. 

Nov 2022

• Johari Dramiga joins the group to work on electrocatalytic modeling of the impact of impurities in hydrogen evolution reaction and solid oxide electrochemical cells

Sep 2022

• Srinivas, Joseph Menicucci, and Raghuram Thiagaraph win a $5,000 seed grant from CAChE Corp to further develop their interactive visualization modules. Check these modules out here. 

Aug 2022

• Chris Rzepa successfully defense his PhD! He will take up a position at Air Products in Allentown

Jun 2022

• Bowen Li defended his PhD in Apr 2022. He will leave Lehigh to take up a Applied Scientist position at Amazon

Dec 2021

• Huijie Tian defends his PhD! Huijie will join Flagship Labs 80 (part of Flagship Pioneering). He's the first PhD graduate of the group!  Congrats, Huijie!

• Aojie Li joins the group! He will work on DFT studies and microkinetic modeling of catalytic transfer hydrogenation

Aug 2021

• Kexin Chen spent six months with the Rangarajan group as a research associate. She will leave Lehigh to join the PhD program at Minneosta! 

May 2021

• This summer, Srinivas and Raghuram Thiagarajan will continue the effort from last year to build interactive web-based visualization tools for science and engineering education. They will mentor a Mountaintop project team of four students: Timothy Odom, Neel Surya, Alex Outkov, and Xu Chen. 

April 2021

• Srinivas wins the NSF CAREER award! The award will support the development of new methods, involving machine learning, DFT, and optimization, to elucidate catalytic transfer hydrogenation of model oxygenates such as acrolein. 

January 2021

• See the news article about our CDSE grant with Mark Snyder and Jeetain Mittal. Mark and Srinivas also received a PITA grant from the commonwealth of Pennsylvania to pursue novel applications of covalent organic frameworks. 

• Our collaborative work on the remarkable performance of bulk gamma alumina as a catalyst for propane dehydrogenation in the presence of H2S was published in Journal of Catalysis.  We discovered that the inexpensive catlayst such as gamma alumina shows remarkable selectivity towards alkane activation in the presence of H2S thereby allowing for processing acidic natural gas and shale gas reserves without pre-treatment. Interestingly, we found that the active sites are likely some defect sites that are known to form on alumina but these are further modified in the presence of H2S rendering them more active and selective and less prone to H2S poisoning (an issue that traditional catalysts  are susceptible to). 

November 2020

• Huijie publishes an article in ACS Catalysis! He proposed a new method to identify dominant parameters in a catalytic reaction system based on data-driven methods that is more robust than the standard method of the degree of rate control that is used in the field of catalysis. He has made his code open source for anyone to try it out. See the article for more details!

• The group welcomes Siddharth Prabhu, who will be co-advised with Prof. Mayuresh Kothare and Srinivas. He will study problems associated with machine learning based discovery of interpretable governing equations of dynamical systems from data. 

September 2020

• Two new papers were published based on Srinivas's postdoctoral work. First is a paper in Nature Communications that for the first time shows, via a combination of DFT and scanning tunneling microscopy (STM) that dynamic edge rearrangements on molybdenum sulfide can allow for adsorption of organosulfur compounds even in the absence of sulfur vacancies. The second is an Accounts of Chemical Research article that discusses how to develop coverage consistent statistically verified microkinetic models that systematically identifies the active sites and reaction mechanism on transition metal catalysts. 

August 2020

• Mountaintop students Anna and Brian did a wonderful job creating online visualization modules for STEM-based learning. Check it out!   A shout out to Raghuram Thiagarajan for all the support! 

July 2020

• Srinivas, Jeetain, and Mark receive an NSF CDSE grant on their collaborative work on designing covalent organic frameworks. Ian Hill at Gustavus Adolphus College is also a collaborator. We're excited!!

June 2020

• Chris Rzepa publishes his first paper as the leading author in JPCC. His work showed that scaling relations of entropy in zeolites extend to numerous categories of molecules. Check it out!

• A team led by Ed Webb of MechE, and comprising of Srinivas, Ganesh Balasubramanian, Lisa Fredin, and Alex Pacheco received an NSF cyberinfrastructure grant to purchase a new HPC cluster. This will significantly enhance the computing capability at Lehigh and lead to interesting new collaborations! 

May 2020

• Srinivas won the John Ochs Award Faculty Achievement Award from the Baker Institute at Lehigh. 

March 2020

• The Rangarajan group is safely physical distancing and working from home in full-swing. Looks like it's going to be a while before we are in Iacocca Hall. 

• The work initiated at UW Madison several years ago finally comes to fruition! Check out Saurabh Bhandari's paper in ACS Catalysis. 

February 2020

• Srinivas and Huijie publish two papers; one on understanding the dehydrogenation of tetrahydropyrrole on Pt(111) as a model liquid organic hydrogen carrier and a paper on showing how simple data-driven corrections can substantially improve microkinetic modeling predictions. 

October 2019

• Our paper on using machine learning techniques, in particular orthogonal polynomial expansions, to estimate vibrational and thermodynamic properties was published in AIChE Journal (invited submission to the second AIChE Futures issue). Check it out here.

• Srinivas gave a talk at the monthly meeting of the NY Catalysis club held in New Jersey.

• The Wachs and Rangarajan groups published a joint review of the state-of-the-art understanding of ethylene oxidation on Ag catalysts. 

September 2019

• Our work in collaboration with Jonas Baltrusaitis was published in ACS Catalysis. H2S, it turns out, can play multiple roles in the hydrogenation of CO2 on molybdenum sulfide! 

August 2019

• Huijie publishes his first paper! It is possible to build accurate binding energy models using multi-task Gaussian Processes. Check it out here. 

June 2019

• Srinivas, Huijie, and Chris attended NAM. Lohit Sharma (Jonas Baltrusaitis group) gave a talk on our collaborative project on understanding the effect of H2S on the reduction of CO2 on molybdenum sulfide catalysts. 

May 2019

• Srinivas co-organized a workshop on foundations and applications of machine learning in molecular and materials science on May 22 - 24, 2019. This workshop brought together over twenty foundational (i.e. those who develop new methods) and  domain (i.e. those who apply state-of-the-art methods to new problems in specific domains) experts to talk about problems at the forefront of the field.  The full program is available here and a news article about the event can be found here. This event was facilitated by I-DISC and funded by the NSF TRIPODS+X program. 

April 2019

• Srinivas co-organized a symposium (along with Luke Roling, Iowa State)  in honor of Prof. Manos Mavrikakis, the recipient of the "Gabor Somorjai Award for Creative Catalysis". This will be a two-day symposium during the Spring ACS Meeting in Orlando and will feature about 25 top international catalysis scientists. 

• Srinivas gave two talks at the Spring ACS Meeting, one on automated analysis of complex reaction networks using RING, optimization, and machine learning and another on DFT-based analysis of the active sites and mechanism of reverse water gas shift reaction on molybdenum sulfide in the presence and absence of H2S.

• Israel Wachs, Jonas Baltrusaitis, and Srinivas has won an internal collaborative award (Lehigh CORE award) to initiate research in the use of modulation excitation spectroscopy and kinetics in developing a detailed mechanistic understanding of catalytic reactions. 

March 2019

• Ann Maula of the Mittal group published a paper in Molecular Systems Design & Engineering on a collaborative research project on shape and functionality requirements for building blocks to assemble into extended crystalline 2D sheets that exhibit Archimedean tilings. 

January 2019

• Srinivas will teach a pilot data science course "ChE 396: Data-driven modeling in chemical sciences and engineering" this Spring. This two-credit 8-week course will cover basics of statistical learning, i.e. what to keep in mind while developing models from data. 

• Srinivas will also teach a six-week module on computational chemistry in "ChE 395: Molecular modeling and simulations" course which he co-teaches with Prof. Jeetain Mittal. 

November 2018

• Ronak, Huijie, and Bowen gave talks at AIChE meeting earlier this month. 

October 2018: 

• The group is getting ready to present three talks at the AIChE annual meeting in Pittsburgh

September 2018: 

• Srinivas to teach the graduate reaction engineering course (CHE 410) to the incoming first year students. 

• Bowen Li successfully passed his qualifiers. Congrats, Bowen!

June 2018: 

• Srinivas gave a talk at the MLSE conference (ChemE track organized by Zachary Ulissi and Andrew J. Medford)

April 2018: 

• Srinivas was appointed the P. C. Rossin Assistant Professor by the Rossin College. This appointment recognizes a faculty member's significant career potential and a proven ability to reach out to other disciplines 

January 2018:

• The group welcomes Christopher Rzepa.  He will be co-advised with Prof. Jeetain Mittal 

• Bowen Li converted to a full-time PhD student. 

October 2017: 

• Srinivas wins the AIChE CAST 2017 W. David Smith Jr. Graduate Publication Award. He will be recognized at the AIChE annual meeting in Minneapolis, MN. 

January 2017:

• Srinivas Rangarajan joins Lehigh U. Ronak Upadhyay and Huijie Tian are the first two graduate student members of the group.  Bowen Li joins as a Masters student.