Journal of Advances in Nanomaterials

6

Authors: Surya Kumar Vatti, Krishnamurthy Konda Ramaswamy, Viswanathan Balasubramanaian

Palladium nano particles in tetrahedral (Td), octahedral (Oh) and spherical (Sp) shapes, supported on hydrotalcite, were synthesized and characterized by XRD and TEM. Td shaped Pd nano particles, with maximum number of exposed (111) planes of Pd, display maximum turn over frequency (TOF) / intrinsic activity for hydrogenation of cinnamaldehyde, indicating the importance of active site geometry. Oh & Sp shaped Pd nano particles that expose both (111) and (100) planes have relatively lower intrinsic activity. For a given reaction, it is essential that appropriate active site geometry, as dictated by the shape/morphology of nano particles be made available. Synthesis and stabilization of such shape controlled nano particles is of prime importance in developing catalysts with higher activity.

8

Authors: J.Vilana, M. Montiel, N. Gimeno, E. Gómez, E. Vallés

Pt-Co thin films have been prepared by means of electrodeposition method, due to the interest of this alloy as catalyst in acid fuel cells. As the stability of the catalyst is fundamental to consider its applicability, the behavior of the films as a function of the composition during voltammetry activation in acidic medium has been studied. The Pt3Co films show high stability, maintaining their morphology, X-ray diffraction profile, composition and high surface area, and show good catalytic behaviour for methanol electro-oxidation in acidic medium. However, the Pt0.7≤x≤1Co films present low stability and evolve during the test to flatter films of lower effective area and Pt3Co stoichiometry, by losing cobalt. Only Pt-Co electrodeposited films of defined compositions show the enough stability and properties to be used as good materials for electro-oxidation processes in acidic media.

14

Authors: Ajalesh Balachandran Nair, Dhanya Vijayan, Ayswarya E P, Rani Joseph, Changwoon Nah

Aluminium hydroxide (ATH) particles were incorporated at different loadings into fluorocarbon rubber (FKM), to study the effect of filler loading on the cure characteristics, mechanical properties, dynamic mechanical properties and thermal stability. The mechanical properties of FKM/ATH composites were better than medium thermal black filled vulcanizates. The storage modulus (E’) of the composites was found to increase due to the enhancement in stiffness. The viscoelastic properties revealed that there is a strong interaction between the polymer and the filler. The dielectric permittivity, AC conductivity and absorption coefficient of the highly ATH loaded systems are much greater than the unfilled and lower systems.