Role of capping agent in the synthesis of zinc–cobalt bimetallic nanoparticles and its application as catalyst and fuel additive

Zinc–cobalt (Zn–Co) bimetallic nanoparticles are used for the production of clean energy and removal of pollutants from wastewater which is always desired for environment and energy. Zn–Co bimetallic nanoparticles are synthesized by the solvothermal method in the presence of two different capping agents i.e. aniline (C₆H₅NH₂) and urea (CH₄N₂O) using methanol as solvent. The effect of two different capping agents on the morphology of bimetallic nanoparticles is studied. The results show that the wrinkles are visible on the surface of bimetallic nanoparticles when aniline is used as capping agent. However, self-oriented nanoflower-like structure of size ⁓60 nm are formed when urea is used as capping agent. Energy dispersive X-ray spectroscopy (EDX) results indicate that Zn and Co atomic ratio is 2:1. Zn–Co nanoflowers are used as a catalyst for the reduction of azo dyes and nitro compounds. Reduction time, reduced concentration, apparent rate constant (k_app) and percentage reduction are studied. The results are analyzed on the basis of substrate structure stability and its affinity toward catalyst. Zn–Co nanoflower is also used as a fuel additive to improve the physicochemical properties of the fuel. Different parameters of fuel are studied such as flash and fire points, cloud and pour points, kinematic viscosity, surface tension and specific gravity. It is observed that Zn–Co nanoflower has a marked effect on these parameters.