Title : Synthesis of ZnO via solution combustion method; study the effect of ignition temperature and fuel quantity
Abstract:
Zinc oxide (ZnO) nanoparticle photocatalyst has been synthesized by solution combustion method using zinc nitrate as the oxidizer and urea as the fuel. The effect of fuel-to-oxidizer ratio and ignition temperature on the properties of synthesized catalysts have been studied. The fuel-oxidant ratio is an important factor during the synthesis because powders with a variable degree of crystallinity and different morphologies were obtained at the fuel-lean and the fuel-rich combustion conditions. Pyramid shape morphology changed to sheet-like morphology with an increase in fuel content. Conversely, reducing the fuel content to the fuel-lean condition has resulted in powders with less surface area, improved crystallinity, and decreased bandgap energy. Properties such as crystallinity, morphology, surface area, and optical properties have been investigated by thermal analysis, X-ray diffraction (XRD), Scanning electron microscopy (SEM), Diffuse reflectance UV–Visible spectra, and Photoluminescence analyses. Ignition temperature is also crucial because it could fix the rate of heating of the precursor mixture. The Samples synthesized at an ignition temperature of 500 °C have shown better photocatalytic activity for both the fuel-lean and fuel-rich conditions. Besides the ignition temperature, ignition time is also an important and optimizable variable as it influences the crystallinity and surface area of the synthesized powders. The degradation of an azo dye at ambient temperature (25±2°C) and solution pH was conducted to evaluate the photocatalytic activity of the synthesized materials. The photocatalysts prepared at fuel-rich conditions show higher photocatalytic dye degradation capability as they have a small crystallite size and more surface area. This study shows that the powder catalyst synthesized at the fuel-oxidant ratio of 1.8 and the ignition temperature of 400 °C have the maximum percentage (99%) of dye degradation in 180 min. The photocatalytic (fuel-oxidant ratio of 1.8) dye degradation follows the pseudo-first order kinetic with a rate constant of 0.0253 min−1, which is 3.14 and 2.88 times higher than that of samples synthesized at fuel-oxidant ratios of 0.6 and 1. The outcomes of the present study help to design more pronounced experiments for the synthesis of photocatalysts by varying fuel amounts and ignition temperatures.
Audience Takeaway:
- Knowledge of ZnO synthesis via solution combustion method
- Effect of various factors such as fuel-to-oxidizer ratio, ignition temperature, ignition time
- Details characterization of synthesized catalyst using SEM, XRD, etc.
- Application of ZnO catalyst for dye degradation and other environmental pollution reduction a
