I hail from Southeastern part of India, from a town called Rajahmundry. I received my bachelor’s degree from Institute of Chemical Technology (ICT), Mumbai in 2016. After that I moved to USA to do my Ph.D. at Purdue University, where I graduated in Aug 2021. During my Ph.D., I have been part of an NSF research engineering center, called CISTAR (Center for Innovative and Strategic Transformation of Alkane Resources). My research as a part of this center focused on using ab-initio methods, mainly Density functional theory (DFT) and Molecular Dynamics (AIMD), to understand reaction mechanisms for catalytic hydrocarbon conversion. The specific reactions I have worked on include propane dehydrogenation (PDH) on alloys and ethylene oligomerization on zeolite catalysts. These studies involved the use of microkinetic modeling to find relevant descriptors, which have been combined with graph-theory-based methods to perform high throughput screening studies. Through these strategies, we were able to find novel catalyst combinations that are highly selective for PDH, which are validated experimentally by our collaborators.
As a part of my professional development during my PhD, I have been fortunate enough to mentor 1 graduate student and 3 undergraduate students as a part of CISTAR’s REU program. I have also been a Teaching Assistant for three courses, Process Control, Process Design and Computational Catalysis. During my undergraduate years, I have done my summer research internship at Indian Academy for Cultivation of Sciences, Kolkata, as a part of a prestigious fellowship IASc-INSA-NASI.
In 2021, I have been awarded the Dick Reitz fellowship from Purdue School of Chemical Engineering and CISTAR. I have also won the best poster presentation during one of the first CISTAR annual meetings. Finally, during my time at ICT, Mumbai, I have won the prominent Ratan Tata scholarship for two consecutive years.
Study of materials for their use in electrochemical transformations aimed at improving the CO2 reduction reaction
The industrial revolution in the past two centuries has greatly increased the greenhouse gas concentrations in the atmosphere; further if the use of fossil fuels is continued at the same level can lead to catastrophic changes in climate. Conversion of CO2 to multi-carbon products using electricity is a viable strategy to reduce the greenhouse gas effects and provide a way to produce high-value chemicals in a sustainable manner. However, the commercial viability of this process is severely affected due to the very low selectivities, or Faradaic efficiencies (FEs) of the hydrocarbons and alcohols produced (methane, ethylene and ethanol). Since pioneering work from Hori and co-workers in late 1980s, Cu still remains the state-of-art catalyst for performing this conversion. Besides, recent work has shown even larger hydrocarbons beyond C2 can be formed through the same electrochemical CO2 reduction (e-CO2R) on oxide-derived Cu and Ni catalysts with non-trivial faradic efficiencies (<25%). This remains a widely under-explored area and holds great prominence due to the high-value of C3+ products, which can further improve the economics of e-CO2R. Even though promising, the reaction mechanisms for C3+ product formation involve large reaction networks with several reaction intermediates (>100). Understanding the mechanisms through which these longer carbon-chain products are formed is crucial for the rational design of catalysts and improve the faradic efficiencies of C3+ products.
Theoretical simulations including Density Functional Theory (DFT) and Ab-initio Molecular Dynamics (AIMD) hold great promise for exploring plausible reaction pathways towards various products in the e-CO2R mechanism. However, to identify rate and selectivity determining steps, data from DFT and AIMD simulations need to be inputted into models suitable for larger time and length scales, such as micro-kinetic modelling (MKM). Under the mean-field approximation, MKM can help answer the questions regarding rate determining steps, reaction fluxes and further assess the coverages of the species with the inclusion of pH and electric potential effects. Even though MKM has been used extensively in thermal heterogeneous catalysis to understand reaction mechanisms, the application of this formalism to electrocatalysis is limited. The challenges include finding appropriate transfer coefficients and inclusion of solvent and electric field effects to estimate the kinetic and thermodynamic barriers. Despite these challenges, a few recent studies have used MKM to explore the reaction pathways till C2 product formation for e-CO2R. The studies agree with experimental results regarding the Tafel slope and pH dependence for C1 vs C2 selectivities. This theoretical approach can further be extended to C3-C4 formations and the plausible reaction mechanisms will be studied using microkinetic modelling, which is the goal of this research project. To summarize, very detailed DFT and AIMD based microkinetic modelling studies will be used to help rationalize the experimental results for e-CO2R on Cu and Ni catalysts, which would further guide the catalytic synthetic routes to optimize selectivities to larger hydrocarbon products.