K. Sethupathi

Bio: K. Sethupathi is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Paramagnetism & Magnetization. The author has an hindex of 20, co-authored 118 publications receiving 1668 citations. Previous affiliations of K. Sethupathi include Indian Institutes of Technology.

Investigation of Spillover Mechanism in Palladium Decorated Hydrogen Exfoliated Functionalized Graphene

Abstract: Porous activated carbon or nanostructured carbon materials have a promising future as hydrogen storage media. The hydrogen storage capacity of nanostructured carbon materials can be further enhanced by spillover of atomic hydrogen from a supported catalyst. In the present work, both of these factors have been put to test to study the hydrogen storage capacity of palladium (Pd) nanoparticles dispersed over the surface of functionalized hydrogen-exfoliated-graphene (Pd/f-HEG). The high-pressure hydrogen storage measurements of HEG and Pd/f-HEG show a hydrogen storage capacity of 0.5 and 1.76 wt % respectively at 25 °C and 2 MPa pressure. Functionalization of graphene facilitates uniform dispersion of Pd nanoparticles, which result in an increased hydrogen storage capacity of graphene by 69%. Heats of adsorption have been calculated for HEG and Pd/f-HEG that are consistent with the theoretical calculations from literature and provide an experimental evidence for the spillover effect.

A glucose biosensor based on deposition of glucose oxidase onto crystalline gold nanoparticle modified carbon nanotube electrode.

Abstract: A new amperometric biosensor, based on deposition of glucose oxidase (GOD) onto crystalline gold (Au) nanoparticle modified multiwalled carbon nanotube (MWNT) electrode, is presented. MWNTs have been synthesized by catalytic chemical vapor decomposition of acetylene over rare-earth-based AB2 (DyNi2) alloy hydride catalyst. Purified MWNTs have been decorated with nanocrystalline Au metal clusters using a simple chemical reduction method. The characterization of metal-decorated CNTs has been done using X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy (TEM), high-resolution TEM, and energy-dispersive X-ray analysis. Amperometric biosensor fabricated by depositing GOD over Nafion-solubilized Au−MWNT electrode retains its biocatalytic activity and offers fast and sensitive glucose quantification. The performance of the biosensor has been studied using cyclic voltammetry, amperometry, and hydrodynamic voltammetry, and the results have been discussed. The fabricated gluc...

Colossal magnetoresistance in the double perovskite oxide La2CoMnO6

Abstract: Polycrystalline sample of La2CoMnO6 has been synthesized by sol-gel technique. The powder x-ray diffraction data confirm the single phase nature of the sample. This compound has monoclinic crystal structure (space group P21/n) at room temperature. The temperature dependence of magnetization in low field shows considerable variation between zero-field-cooled and field-cooled magnetization curve below ∼210 K (TC) and it follows Curie–Weiss law in the paramagnetic region. The hysteresis loop at 5 K indicates a coercive field of ∼6 kOe and remnant magnetization of ∼2.32 μB/f.u. The temperature dependence of the resistivity data shows semiconductorlike behavior in the temperature range of 5–350 K and follows variable range hopping conduction mechanism in the temperature range 215–350 K. A colossal magnetoresistance of ∼80% is observed at 5 K in an applied field of 80 kOe and MR has a negative sign.

Recent Advances in Electrocatalysts for Oxygen Reduction Reaction

Abstract: The recent advances in electrocatalysis for oxygen reduction reaction (ORR) for proton exchange membrane fuel cells (PEMFCs) are thoroughly reviewed. This comprehensive Review focuses on the low- and non-platinum electrocatalysts including advanced platinum alloys, core–shell structures, palladium-based catalysts, metal oxides and chalcogenides, carbon-based non-noble metal catalysts, and metal-free catalysts. The recent development of ORR electrocatalysts with novel structures and compositions is highlighted. The understandings of the correlation between the activity and the shape, size, composition, and synthesis method are summarized. For the carbon-based materials, their performance and stability in fuel cells and comparisons with those of platinum are documented. The research directions as well as perspectives on the further development of more active and less expensive electrocatalysts are provided.

Graphene, related two-dimensional crystals, and hybrid systems for energy conversion and storage

Abstract: Graphene and related two-dimensional crystals and hybrid systems showcase several key properties that can address emerging energy needs, in particular for the ever growing market of portable and wearable energy conversion and storage devices. Graphene's flexibility, large surface area, and chemical stability, combined with its excellent electrical and thermal conductivity, make it promising as a catalyst in fuel and dye-sensitized solar cells. Chemically functionalized graphene can also improve storage and diffusion of ionic species and electric charge in batteries and supercapacitors. Two-dimensional crystals provide optoelectronic and photocatalytic properties complementing those of graphene, enabling the realization of ultrathin-film photovoltaic devices or systems for hydrogen production. Here, we review the use of graphene and related materials for energy conversion and storage, outlining the roadmap for future applications.