Production of granulated-copper oxide nanoparticles for catalytic application

Abstract

Ultra fine CuO nanoparticles in the range of 2 ± 0.2 nm were synthesized by the supercritical hydrothermal method in a batch reactor. It was demonstrated that elevating the pH of the Cu2+ precursor solution to around 6 (neutral condition) not only does not lead to excessive agglomeration of the particles, but also reduces particle size and in general promotes their nanoscale characteristics. Prepared nanoparticles were immobilized in the biopolymeric matrix of barium alginate and calcined at different temperatures resulting in microspherical granules of high porosity and elevated mechanical strength. The fabricated samples were characterized using x-ray diffractometry (XRD), transmission and scanning electron microscopy (TEM and SEM), nitrogen adsorption analysis (BET), mechanical testing, and temperature programmed reduction (TPR). It was found that topochemical models based on a nucleation growth mechanism fail in proper fitting of the TPR data. Instead, a generalized Sestak model in which different physicochemical mechanisms such as the mass action law are taken into account gives a satisfactory regression of the kinetics behavior.