ABSTRACT Highly selective nickel nanocatalysts were synthesized by modified polyol reduction methods with different surfactants and solvents. These nanoparticles were characterized by UV-Vis spectroscopy. The effect of anionic-sodium dodecyl sulfate(SDS), cationic-N-cetyl- N,N,N trimethyl ammonium bromide (CTAB) and neutral surfactant- polyvinyl pyrrolidone (PVP) was studied by X-ray diffractometer (XRD) technique. Morphology, particles size, and oxidation state of nickel nanoparticles (below 10 nm) were confirmed by Field Emission Scanning Electron Microscopy, High Resolution Transmission Electron Microscopy and X- ray Photoelectron Spectroscopic techniques, respectively. The study reveals that the particles using ethylene glycol as reductant and PVP as capping agent are smallest (2.4 nm), amorphous, homogeneous and less dispersed. Further, particles with smaller size are used as catalysts in the degradation of acid orange10 dye by hexacyanoferrate(III) ions in aqueous alkaline medium. The particles size show good catalytic activity as compared to nickel precursor salts due to their small size.