Electrical explosion of nickel wire as an efficient method for large-scale preparation of nickel oxide nanopowders: evaluation of operational key factors on the average crystallite size and average size distribution using response surface methodology (RSM)

Abstract

The electrical explosion of wire (EEW) method provides a sufficiently route for large-scale preparation of nickel oxide nanopowders (NiO-NPs) with a small degree of contamination. In this study, Central composite design of the response surface methodology (RSM) was firstly employed to evaluate the average crystallite size (ACS) and average size distribution (ASD) of NiO-NPs. Twenty types of NiO-NPs were prepared by adjusting three operating parameters (wire diameter, the distance between two electrodes and the voltage) at five levels by the method of multiple variable analysis. The check experiments revealed that all the three operating parameters have significant effect on the ACS and ASD of NiO-NPs. For each response, a suitable second-order regression equation was obtained by applying analysis of variance. In addition, the results revealed acceptable agreement among experimental data and predicted results. Moreover, the optimum region for production of NiO-NPs with size below 100 nm by EEW method was obtained. Characterization of NiO p-type semiconductor in terms of size distribution, morphology, chemical composition and phase structure was carried out by TEM, SEM/EDX, XRD and BET analyses. The results nominated the EEW technique as a unique method for large-scale and economic preparation of NiO-NPs with defined structural features.