Research

Novel Material Development

Catalytic Site Investigation

Energy & Environmental Applications

Catalytic processes are used globally for industrial applications worth trillions of dollars per year in pollution abatement, chemical, pharmaceutical, manufacturing, and energy sectors. Increasing demands for environment-friendly technologies in the backdrop of the current climate change crisis requires the development of novel catalytic materials for emerging sustainable chemical processes. We use principles from chemical engineering, materials science, and physical chemistry to engineer new catalytic materials towards these goals. We start by investigating the governing mechanisms of catalytic reactions on well-defined nanostructured materials. We subsequently use the developed molecular-level insights and structure-property relations to synthesize effective catalysts with targeted architecture, composition, and properties. Our focus is on reactions related to energy and environment, with emphasis on the chemistry of small building blocks: hydrogen, carbon dioxide, and methane.

Research Directions

Morphology-controlled Catalysts for Sustainable CO2 Conversion 

Catalytic conversion of CO2 to produce fuels and chemicals is attractive in prospect because it provides an alternative to fossil feedstocks and the benefit of converting and cycling CO2 on a large scale. In today's technology, processes for direct conversion of CO2 to fuels and chemicals are still far from large-scale applications because of processing challenges that may be best addressed by the discovery of improved catalysts—those with enhanced activity, selectivity, and stability. 

Conventional supported solid catalysts present non-uniform heterogeneous mixtures of variously segregated sites, that make it nearly impossible to purposefully tune the active sites to promote specific reactions. We focus on creating controlled tailormade catalyst architectures such as core-shell/ yolk-shell morphologies with precise control on catalytic site and interfaces, that allow us to optimize the catalytic sites at the nanoscale using fundamental understanding of the catalytic chemistry and reaction mechanism.

We have developed novel multi-functional core-shell catalysts for CO2 conversion by CO­2 reforming of methane (DRM) and CO2 hydrogenation that address challenges such as catalyst sintering, unselective coke formation, and activity loss by promoting the formation of beneficial interfaces among complementary functional materials.  

Visible light driven CO2 conversion using plasmonic materials 

After successfully developing catalysts for thermally driven CO2 conversion, we are now venturing into the exciting new area of "Photothermal" catalysis, with the aim of driving the conversion using renewable solar energy. Photothermal catalysts use both thermal and photochemical contributions of sunlight to drive catalytic reactions. By utilizing the full spectrum of sunlight (UV, visible, and IR spectra), photothermal catalysts can achieve several orders of magnitude higher yields than traditional photocatalysts and can transform the landscape of solar fuel production. The development of appropriate catalysts is critical to ensure effective combination of light and heat to achieve high product yields under realistic sunlight conditions. 

We are working on developing new hierarchical plasmonic photothermal catalysts for CO2 conversion to syn-gas and methane. Our strategy is to enhance efficient transport of electrons, heat, and reactants among catalytic and plasmonic sites to improve photothermal CO2 conversion and solar-to-fuel efficiency.


Catalysis for Plasma-driven Sustainable Conversions 

Non-thermal plasma (NTP) has emerged as a promising technology for converting hard-to-activate molecules such as CH4, CO2, N2 etc. In contrast to conventional thermal catalysis, non-thermal plasma driven conversion offers benefits of low temperature conversion, high conversions, and most importantly, the option of using renewable electricity to drive the reaction – which is critical for future decarbonization of the chemical industry.

On the flip side, plasma driven chemistry is inherently unselective, resulting in wide product distributions. Product selectivity and energy efficiency of NTP may be improved by integration of appropriate catalysts with the plasma. The catalyst properties required in a plasma-driven process, however, differ in principle from that of conventional thermal catalysts, throwing up exciting challenges for catalyst development for such processes.

We develop new catalysts that can be coupled with non-thermal plasma to selectively guide the reaction towards desirable products in reactions such as Non-oxidative Methane Coupling to C2+ hydrocarbons, CO2 Conversion to CO, and Reforming of Biomass-derived Tar.

Operando investigation of active sites in Single Atom Catalysts & MOFs

Determination of catalytically active sites on heterogenous solid catalysts is complicated by the inherent non-uniformity of their structures. Single atom catalysts (SACs) and metal-organic frameworks (MOFs) present unique opportunities to experimentally investigate catalytic sites on “solid” catalysts at molecular and atomic levels because of their more uniform and atomically precise structures compared to conventional supported catalysts. Controlled experiments on such materials can provide scientific information that is critical to establishing a scientific understanding of catalysis on solids and manipulating their structures to achieve activities and selectivities currently achievable only by uniform homogeneous catalytic systems.

We use a vast array of ex situ and in situ characterization techniques coupled with mechanism and performance studies to determine catalytically active sites on SACs and MOFs as prototype catalysts. We collaborate with theorists for quantum mechanical calculations to validate our experimental observations.


Identification of Active Sites for Methane Reforming 

on Pt Single Atom Catalyst

Collaborations

 We collaborate with brilliant minds at:

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