Synthesis of Cobalt Oxide Nanoparticles and Their Catalytic Application in Esterification Reactions

Abstract

Cobalt oxide nanoparticles (CoNPs) have garnered a lot of interest because of their distinctive physicochemical properties and wide catalytic applications. This study reports the synthesis of Co nanoparticles using both green and conventional chemical methods, followed by structural characterization and evaluation of their catalytic performance in esterification reactions. In the green synthesis approach, pomegranate peel extract was employed as a natural reducing and stabilizing agent. The synthesized nanoparticles were characterized using FTIR, SEM, XRD, and UV–Vis spectroscopy. XRD analysis using the Debye Scherrer equation revealed that green-synthesized nanoparticles exhibited smaller crystallite sizes (1–20.4 nm) compared to chemically synthesized nanoparticles (2.6–82 nm). FTIR results confirmed the formation of cobalt oxide through characteristic CoO stretching vibrations. The catalytic activity of the synthesized nanoparticles was evaluated in the esterification of acetic acid with ethanol at 80 °C for 3 hours. The green-synthesized nanoparticles demonstrated superior catalytic performance, achieving 91.32% acid conversion compared to 85.64% for chemically synthesized nanoparticles. While, the effect of reaction time (60, 120, 180 min), at 80 oC on. For the two catalysts used, the acid conversion increased with reaction time. The enhanced catalytic efficiency is attributed to the smaller particle size and the existence of plant-derived biomolecules acting as capping agents. These findings highlight the effectiveness of green synthesis as an eco-friendly and economical efficient method for producing efficient nanocatalysts.