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Dive into the research topics where Leena George is active.

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Featured researches published by Leena George.


RSC Advances | 2016

Valorization of coffee bean waste: a coffee bean waste derived multifunctional catalyst for photocatalytic hydrogen production and electrocatalytic oxygen reduction reactions

Sreekuttan M. Unni; Leena George; Siddheshwar N. Bhange; R. Nandini Devi; Sreekumar Kurungot

Here, we report the valorization of coffee bean waste (CBW) by producing nitrogen doped porous carbon (p-Cof) having both photocatalytic and electrocatalytic properties using a silica templating method. Morphological investigation of p-Cof reveals the presence of assemblies of highly porous flat carbon blocks. p-Cof exhibits a high surface area (1213 m2 g−1) and a wide range of micro- and mesopores with good electrical conductivity. Along with this, the surface of p-Cof displays the presence of graphitic and pyridone-type nitrogen coordinations, which help p-Cof to perform as a multifunctional catalyst as revealed from its catalytic activities towards photocatalytic hydrogen production (PHP) and electrocatalytic oxygen reduction reactions. p-Cof produces 334 μmol h−1 g−1 of hydrogen from water under visible light and 575 μmol h−1 g−1 of hydrogen under solar light irradiation with excellent stability. Along with this, p-Cof also displays improved oxygen reduction reaction (ORR) activity in alkaline medium. A better onset potential (0.91 V vs. RHE) and half-wave potential (0.75 V vs. RHE) are displayed by p-Cof compared to the catalyst derived from the simple annealing of CBW without employing the silica template. Along with the better electrochemical activity, p-Cof shows excellent ORR kinetics and electrochemical stability compared to the current state-of-the-art Pt/C.


New Journal of Chemistry | 2014

Green synthesis of novel polyoxoanions of tungsten containing phosphorus as a heteroatom: characterization, non-isothermal decomposition kinetics and photocatalytic activity

Bessy D'Cruz; Jadu Samuel; Mulloor Kesavapillai Sreedhar; Leena George

Synthesis of cetylpyridinium phosphotungstate (CPW) nanospheres was carried out by using sodium tungstate and a structure directing cationic surfactant, cetyl pyridinium chloride (CPC), at room temperature by applying green chemistry principles. The composition and morphology of the nanospheres were established by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA) and inductively coupled plasma atomic emission spectroscopic (ICP-AES) techniques. Thermal properties of the nanoparticles were investigated by non-isothermal analysis under a nitrogen atmosphere at four different heating rates 10, 15, 20 and 25 °C min−1. The thermal decomposition of CPW occurred in two stages. The activation energy values at each stage of thermal decomposition for all heating rates were calculated by Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunnose (KAS) methods. The invariant kinetic parameter (IKP) method and the master plot method were also used to evaluate the kinetic parameters and mechanism for the thermal decomposition of CPW. The photocatalytic water oxidation mechanism using a CPW catalyst in the presence of a platinum (Pt) co-catalyst enhances the H2 evolution, which was found to be 2.0 mmol g−1 h−1.


RSC Advances | 2014

Green chemical incorporation of silicon into polyoxoanions of molybdenum: characterization, thermal kinetics study and their photocatalytic water splitting activity

Bessy D'Cruz; Jadu Samuel; Leena George

Cetylpyridinium silicomolybdate (CSM) nanorods were successfully synthesized by applying green chemistry principles using sodium molybdate and a structure directing cationic surfactant, cetyl pyridinium chloride (CPC) at room temperature. The composition and morphology of the nanorods were established by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TG) and inductively coupled plasma atomic emission spectroscopic (ICP-AES) techniques. The thermal decomposition kinetics of CSM nanorods were investigated by a non-isothermal thermogravimetric analyzer at various heating rates. The thermal decomposition of CSM occurred in two stages. The activation energies of the first and second stages of thermal decomposition for all heating rates have been estimated using the iso-conventional methods of Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS) and the results are found to be in good agreement with each other. The invariant kinetic parameter (IKP) method and master plot method were also used to evaluate the kinetic parameters and mechanism for the thermal decomposition of CSM. The photocatalytic water oxidation mechanism using the CSM catalyst in the presence of platinum (Pt) co-catalyst enhances the H2 evolution and was found to be 1.946 mmol g−1 h−1.


Advanced Energy Materials | 2016

Low Band Gap Benzimidazole COF Supported Ni3N as Highly Active OER Catalyst

Shyamapada Nandi; Santosh K. Singh; Dinesh Mullangi; Rajith Illathvalappil; Leena George; C. P. Vinod; Sreekumar Kurungot; Ramanathan Vaidhyanathan


Nanoscale | 2014

Nitrogen-doped graphene interpenetrated 3D Ni-nanocages: efficient and stable water-to-dioxygen electrocatalysts

Vishal M. Dhavale; Sachin S. Gaikwad; Leena George; R. Nandini Devi; Sreekumar Kurungot


Journal of Physical Chemistry C | 2015

Surface Site Modulations by Conjugated Organic Molecules To Enhance Visible Light Activity of ZnO Nanostructures in Photocatalytic Water Splitting

Leena George; Subrahmanyam Sappati; Prasenjit Ghosh; R. Nandini Devi


Journal of Molecular Catalysis A-chemical | 2016

Photocatalytic H2 evolution from water–methanol mixtures on InGaO3(ZnO)m with an anisotropic layered structure modified with CuO and NiO cocatalysts

Soumya B. Narendranath; Saranya V. Thekkeparambil; Leena George; Shibin Thundiyil; R. Nandini Devi


Thermochimica Acta | 2014

Characterization, non-isothermal decomposition kinetics and photocatalytic water splitting of green chemically synthesized polyoxoanions of molybdenum containing phosphorus as hetero atom

Bessy D’Cruz; Jadu Samuel; Leena George


Catalysis Today | 2017

Sensitizing with short conjugated molecules: Multimodal anchoring on ZnO nanoparticles for enhanced electron transfer characteristics, stability and H2 evolution

Leena George; Subrahmanyam Sappati; Prasenjit Ghosh; R. Nandini Devi


Physical Chemistry Chemical Physics | 2016

Understanding the electron transfer process in ZnO–naphthol azobenzoic acid composites from photophysical characterisation

Leena George; Athira K. Kunhikannan; Rajith Illathvalappil; Divya Ottoor; Sreekumar Kurungot; R. Nandini Devi

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R. Nandini Devi

Council of Scientific and Industrial Research

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Sreekumar Kurungot

Academy of Scientific and Innovative Research

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Prasenjit Ghosh

Jawaharlal Nehru Centre for Advanced Scientific Research

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Rajith Illathvalappil

Council of Scientific and Industrial Research

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Subrahmanyam Sappati

Indian Institute of Science Education and Research

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Athira K. Kunhikannan

Council of Scientific and Industrial Research

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C. P. Vinod

Council of Scientific and Industrial Research

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