Senior Research Fellow
Jesna Louis joined Department of Polymer Science and Rubber Technology at Cochin University of Science and Technology under the mentorship of Dr. Honey John in April 2017. Her research interests center around the opto-electronic application of semiconductor oxides and its organic/ inorganic hybrids. Currently she is also working in a project titled ‘Development of superhydrophilic graphene/semiconductor oxide nanohybrids for self-cleaning applications’ funded by DST-SERB. She holds a BS-MS degree in Chemistry (major) and Biology (minor) from Indian Institute of Science and Education Research, Bhopal. During her masters she worked in several projects on supercapacitor and white light emitting materials for organic light emitting diodes.
Google Scholar Link
Jesna Louis, Nisha T Padmanabhan, Madambi K Jayaraj, and Honey John, “Crystal lattice engineering in a screw-dislocated ZnO nanocone photocatalyst by carbon doping”, Mater. Adv., 2022. View the Article
E. J. Jelmy, Nishanth Thomas, Dhanu Treasa Mathew, Jesna Louis, Nisha T. Padmanabhan, Vignesh Kumaravel, Honey John, and Suresh C. Pillai, Impact of structure, doping and defect-engineering in 2D materials on CO2 capture and conversion React. Chem. Eng., 2021, View the Article
Nisha T Padmanabhan, Nishanth Thomas, Jesna Louis, Dhanu Treasa Mathew, Priyanka Ganguly, Honey John, Suresh C Pillai “Graphene coupled TiO2 photocatalysts for environmental applications: A review”, Chemosphere, 129506, 2021. Full Article
J. Louis, M. K. Kavitha, V. Anjana, M. K. Jayaraj, H. John, A facile surfactant assisted hydrothermal synthesis of ZnO and graphene loaded ZnO for efficient photocatalytic self-cleaning. Materials Research Express 6, (2020); published online Epub01/21 (10.1088/2053-1591/ab6e3a).
Superhydrophilicity and photocatalysis are of great importance for self-cleaning applications. We report the synthesis of ZnO and ZnO loaded graphene nanostructures at different pH values with exposed polar facets by a simple hydrothermal method. Cetyltrimethylammonium bromide is used as surfactant and the synthesis is carried out without the aid of high temperature and demonstrated to have a superior photocatalytic activity. We observed a reduction in band gap for graphene loaded ZnO samples. Further, a one-step spin coating method is used for the preparation of optically transparent and photoinduced superhydrophilic ZnO hybrid films. We investigated the effect of cetyltrimethylammonium bromide capping agent on crystal growth and morphology of as synthesised samples. An effective improvement in photocatalytic activity of the nanohybrid (~100%) compared to pure ZnO (85%) is observed within 150 min. This can be attributed to the synergetic interaction of the components of the hybrid. Also, the hybrid samples coated on the glass substrate exhibits good transparency and superhydrophilicity upon UV irradiation. An unexpected transmittance as high as 84%–97% throughout most of the visible light region of the spectrum of the hybrid samples along with good photocatalytic efficiency and photoinduced superhydrophilicity makes the samples more suitable for self-cleaning applications.
A two-step solvothermal synthesis was adopted to prepare AgXSe2-TiO2 (X = In, Bi) composites. DFT study of the pristine parent samples showed the formation of the hexagonal phase of AgBiSe2, and tetragonal phase of AgInSe2 and TiO2, which corroborated the experimentally synthesised structures. Both the AgBiSe2-TiO2 and AgInSe2-TiO2 composites displayed enhanced visible light absorption and reduced band gap in the UV-DRS patterns. The XPS results exhibited a shift in binding energy values and the TEM results showed the formation of spherical nanoparticles of both AgBiSe2 and AgInSe2. The PL signals displayed delayed recombination of the photogenerated excitons. The as synthesised materials were studied for their photocatalytic efficiency, by hydrogen generation, degradation of doxycycline, and antimicrobial disinfection (E. coli and S. aureus). The composite samples illustrated more than 95% degradation results within 180 min and showed 5 log reductions of bacterial strains within 30 min of light irradiation. The hydrogen production outcomes were significantly improved as the AgBiSe2 and AgInSe2 based composites illustrated 180-fold and 250-fold enhanced output compared to their parent samples. The enhanced photocatalytic efficiency displayed is attributed to the delayed charge recombination of the photogenerated electron-hole pairs in the AgXSe2-TiO2 interface. Formation of a p-n nano heterojunction for AgBiSe2-TiO2 and type II heterojunction for AgInSe2-TiO2 composite are explained.
The investigations on anthropogenic carbon dioxide (CO2) capture and conversion play a vital role in eradicating global warming and the energy crisis. In this context, defect-engineered two-dimensional (2D) nanomaterials have received much attention in recent years. Herein, the significance of 2D nanomaterials such as graphene, transition metal dichalcogenides, hexagonal boron nitride, MXenes, graphitic carbon nitride, metal/covalent organic frameworks, nanoclays, borophenes, graphynes and green phosphorenes for CO2 capture and conversion has been emphasized. Further, the intrinsic mechanism of CO2 adsorption and conversion is discussed in detail. Theoretical and experimental studies among 2D materials highlight that N-doped porous adsorbents based on graphene and MXenes are more suitable for CO2 adsorption applications. Also, more emphasis is given to outlining and discussing the role of various 2D nanomaterials and their hybrids as photocatalysts, electrocatalysts, photoelectrocatalysts, and thermocatalysts to transform CO2 into valuable products. Although immense efforts are deployed in developing 2D catalysts for the conversion of CO2, challenges such as agglomeration, poor yield, difficulties in analysing the 2D structures for catalytic factors, poor knowledge and in-depth understanding of the reaction mechanisms, high cost, etc. limit their large scale production and commercialization. More detailed theoretical and experimental investigations are required to develop 2D nanostructures with optimum properties for large-scale capture and conversion of CO2.