Tetrahydrofuran hydroperoxide (THF-HPO) and 3-aminopropyltrimethoxysilane (3-APTMS) mediated controlled synthesis of palladium (Pd) and palladium-gold bimetallic (Pd-Au) nanoparticles are reported and characterized by TEM, AFM and UV-Vis spectroscopy. A comparative study on the formation of bimetallic nanoparticles via sequential and simultaneous reduction of metal salts is reported. The nanogeometry of as synthesized nanoparticles decreases with an increase in 3-APTMS concentration. The effect of variable nanogeometry of palladium nanoparticles (PdNPs) on the reversible redox electrochemistry of ferrocene monocarboxylic acid (Fc-COOH) is examined with major findings; (1) the homogeneous redox electrochemistry of Fc-COOH tend to become sluggish in the presence of 3-APTMS, (2) the presence of palladium significantly improve the reversible redox behavior of ferrocene derivative with considerable decrease in anodic and cathodic peaks separation, (3) there is an increase in electrocatalytic efficiency during electrochemical sensing of ascorbic acid as a function of nanogeometry and (4) the PdNPs also show admirable peroxidase mimetics activity with remarkable dependence of the same on 3-APTMS concentrations. (C) 2014 Elsevier Ltd. All rights reserved.