Research Projects

Plasmonic nanoparticles (NPs) and quantum dots (QDs) have an exceptional ability to store as well as convert light energy into ‘hot’ charge carriers. As a result, performing chemistry with plasmonic and quantum materials is gaining enormous attention in forming and breaking of high-energy chemical bonds. The efficiency of a NP and QD photocatalysed reaction depends on two major factors: the (i) dynamics of hot carriers, comprised of processes such as hot carrier generation, thermalization, complex charge transfer processes, etc., and (ii) dynamics of reactant molecules on the catalyst surface, consisting of adsorption-desorption kinetics, reaction intermediates, reaction pathways, etc. However, the emerging areas of plasmonic and QD photocatalysis and photoelectrocatalysis are deprived of holistic insights on molecular-level reaction pathways and structure-activity relationships. The submitted project proposes to use operando techniques to capture precise information on molecular-level structure-activity relationships in plasmonic and QD photo(electro)catalysis. Some of the information that will be gained includes identification of intermediates, adsorbates, reaction pathways, kinetics, and catalyst poisoning. Plasmonic metal NPs (e.g. AuNPs, CuNPs, AgNPs, etc.) and QDs (e.g. InP, CuInS2, ZnS etc.) will be used as the photo(electro)catalysts, owing to their large absorption cross-section and strong localized surface plasmon resonance in the visible and NIR regions. Both these properties are highly sensitive to the changes in the local environment, which makes plasmonic NPs and QDs ideal for real-time and in-situ monitoring of photo(electro)catalytic reactions occurring on their surfaces. The progress of the photo(electro)catalytic reactions using plasmonic NP and QDs will be monitored using in-situ techniques, mainly diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The use of operando tools will provide vital inputs on dynamically formed adsorbates, intermediates, and reaction pathways, which are often undetectable during the routine measurements. We plan to study some of the fundamentally challenging chemical transformations such as ammonia synthesis, carbon dioxide reduction, cofactor regeneration, etc. A conclusive knowledge on the prominent pathways involved in these reactions on the surface of a NP and QD catalysts is still missing. Likewise, achieving high product selectivity and efficiency is still challenging in NP and QD photo(electro)catalysis, due to the lack of precise knowledge on catalyst-reactant interactions. In summary, the submitted proposal foresees the power of operando approaches to unlock some of the chemical mysteries in the emerging area of plasmonic and QD catalysis, thereby providing viable solutions to several fundamentally challenging and industrially useful chemical reactions. Our proposal not only foresees the use of operando approaches to gain valuable molecular level mechanistic insights in photocatalysis and photoelectrocatalysis but also align well with the global target of clean energy and sustainability in chemical synthesis.