Pengaruh Laju Aliran Gas pada Reaktor DC Termal Plasma Terhadap Karakteristik Nanomaterial ZnO

Abstract

The synthesis of Zinc Oxide (ZnO) nanoparticles using conventional methods is often constrained by high production costs and difficulties in mass production scale application. This study aims to examine the effect of gas flow rate variations (10 l/min, 15 l/min, and 20 l/min) in a DC thermal plasma reactor on the morphology, particle size, and crystal structure of ZnO nanomaterials. The research method used was experimental, utilizing Zinc (Zn) powder with a size of <45 µm and 97.1% purity as the precursor, processed at a current of 65 A for an ignition time of 40 seconds. Characterization of the synthesized product was evaluated using Scanning Electron Microscope (SEM) for morphology and particle size analysis, and X-Ray Diffraction (XRD) for structure and crystallite size analysis. SEM observations revealed that the particle morphology tended to be irregular and agglomerated; the 10 l/min variation was granular and semi-polygonal, 15 l/min leaned towards semi-spherical, and 20 l/min was granular and semihexagonal. The resulting particle size ranged from 8–253 nm (10 l/min), 14–237 nm (15 l/min), and 16–140 nm (20 l/min), with sizes under 100 nm dominating all variations. XRD testing confirmed that all variations successfully formed the stable hexagonal wurtzite crystal phase of ZnO. The average crystallite size obtained was 31.57 nm at a gas flow rate of 10 l/min and increased to 34.66 nm at 20 l/min due to the reduced particle residence time in the plasma zone. In conclusion, gas flow rate variations significantly affect the characteristics of ZnO nanomaterials, and the DC thermal plasma method is proven successful in producing quality wurtzite-phase ZnO.