Research Projects

Natural sunlight, comprising >50% near infrared (NIR) irradiation, is an abundant source of renewable energy. Photoirradiation from natural sunlight can be utilized for the excitation of charge carriers in a semiconducting material, along with increasing the localized surface temperature of the catalyst, through the plasmon-induced photothermal effect. This project is focused on complete utilization of broad-spectrum photo-illumination through the design and development of suitable core-shell functional catalysts with photothermally active core, comprising of spherical defect-rich spinel mixed metal oxides and bimetallic metal organic frameworks (MOFs) as the shell layer. Additionally, a polydopamine (PDA) coating will be introduced on the external MOF surface to increase photothermal activity and impart dual functionalities: regeneration of surface-bound metallic redox cycles (i.e., Fe3+/Fe2+, Co2+/Co3+, Cu+/Cu2+) and resisting the dissipative loss of photothermal energy through insulating layer. Broad spectrum photoirradiation will be used to excite and separate the e-/h+ pairs, along with generation of hot charge carriers in the defect-rich oxides and MOF layer. The surface-bound redox cycles and photothermally generated e-/h+ pairs will lead to activation of different oxidants (i.e., persulfates) to generate numerous reactive species (hydroxyl, sulfate, superoxide, etc.) which will lead to complete degradation and significant mineralization of different refractory organics in aqueous medium. Along with Xe lamp-based simulated light, natural sunlight will also be utilized for photothermal remediation of contaminated real-life water, using a Frensel lens arrangement. Furthermore, macrosized mixed matrix catalytic media will be developed for continuous mineralization of organic contaminants in real-life water, in a newly designed photothermal reactor. The contaminated water will contain various emerging organic contaminants (i.e., microplastics, pharmaceuticals, herbicides, chlorophenols). The catalytic media will be developed either as floatable or submerged form. Finally, the stability and reusability of the developed catalysts over multiple catalytic cycles, along with the residual toxicity of the treated water, will be studied through in-depth characterization and analysis techniques. Multiphysics based simulation studies will be carried out to determine the temporal variation of surface temperature of model spherical nanocatalysts and surrounding fluid medium, in presence of photoirradiation. Moreover, continuum-based mass transfer-kinetic model will be employed to simulate the variation of average residual contaminant concentration in the reaction medium, for both single component and multicomponent systems, and optimized mass transfer and kinetic parameters will be evaluated. Overall, this study will be a holistic approach towards utilization of complete solar irradiation for sustainable water remediation through photothermal catalysis.