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Ghosh S.,se National Center For Basic Science Block Jd | Ghosh S.,University Paris - Sud | Remita H.,University Paris - Sud | Remita H.,CNRS Laboratory of Chemical Physics | And 7 more authors.
Journal of Materials Chemistry A | Year: 2015

One of the significant challenges for the commercialization of direct ethanol fuel cells (DEFCs) is the preparation of active, robust, and low-cost catalysts. In this work, a facile and reproducible method is demonstrated for the synthesis of Pd assembled nanostructures in a hexagonal mesophase formed by a quaternary system (Pd-doped water, surfactant, oil, and cosurfactant) via photoirradiation. The formation of Pd nanostructures in the confined region of hexagonal mesophases was further supported by water relaxation dynamics study using a solvation probe. The mesophases can be doped with high concentrations of a palladium salt (0.1 M) without any disturbance to the structure of the mesophases which results in a high yield and facilitates the clean synthesis of Pd nanostructures without using any toxic chemicals. Electrochemical measurement confirms that the as-prepared catalysts exhibit significant electrocatalytic activity for ethanol oxidation in alkaline solution. Additionally, we present an alternative strategy using reduced graphene oxide nanosheets in combination with Nafion (a proton conducting phase) as a support, revealing the pronounced impact on dramatically enhanced electrocatalytic activity and stability of Pd nanostructures compared to Nafion alone. This unique combination allowed the effective dispersion of the Pd nanostructures that is responsible for the enhancement of the catalytic activity. Our approach paves the way towards the rational design of practically relevant catalysts with both enhanced activity and durability for fuel cell applications. © The Royal Society of Chemistry.2015.

Singh A.K.,se National Center For Basic Science Block Jd | Sarkar D.,se National Center For Basic Science Block Jd | Khan G.G.,University of Calcutta | Mandal K.,se National Center For Basic Science Block Jd
Journal of Materials Chemistry A | Year: 2013

This study demonstrates a scheme to design and fabricate a novel 1D core/shell Ni/NiO nano-architecture electrode as a pseudocapacitor with significantly improved capacitive performance through hydrogenation. The specific capacitance of the as prepared 1D core/shell Ni/NiO nanoheterostructure (717 F g-1 at a scan rate of 2 mV s-1) is nearly 1635 F g-1 after the hydrogenation. The improved pseudocapacitive properties of hydrogenated Ni/NiO nano-heterostructures are attributed to the incorporation of the hydroxyl groups on the NiO surface due to hydrogenation, where the metallic Ni nanowire core of this unique 1D core/shell heterostructure serves as the efficient channel for the fast electron conduction to the current collector. The H-Ni/NiO nanoheterostructures exhibit good rate capability (retaining nearly 60% of their initial charge) and good long-term cycling stability with an excellent specific energy and power density of 49.35 W h kg-1 and 7.9 kW kg-1, respectively, at a current density of 15.1 A g-1. This study demonstrates that the H-Ni/NiO nano-heterostructure is very promising for next generation high-performance pseudocapacitors. © 2013 The Royal Society of Chemistry.

Banik M.,Indian Statistical Institute | Das S.,se National Center For Basic Science Block Jd | Majumdar A.S.,se National Center For Basic Science Block Jd
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015

Incompatible measurements in quantum theory always lead to Einstein-Podolsky-Rosen (EPR)-Schrödinger steering. Channel steering, which is a generalized notion of EPR-Schrödinger steering, has been introduced recently. Here we establish a connection between lack of joint measurability and channel steering. © 2015 American Physical Society.

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