Synthesis of α and γ phase of aluminium oxide nanoparticles for the photocatalytic degradation of methylene blue under sunlight: A comparative study

Abstract

One promising approach towards the degradation of organic pollutants in wastewater is aluminum metal oxide nanoparticles as photocatalysts. This study involves synthesizing aluminum oxide nanoparticles (Al2O3 NPs) using two different methods, i.e., precipitation and sol–gel process. We have investigated the structural, morphological, and optical properties of both Al2O3 NPs using various characterization techniques. From XRD analysis, as-prepared precipitation, and sol–gel Al2O3 NPs, exhibited the cubic structure of γ-phase and hexagonal wurtzite structure of α-phase, with crystallite sizes of 36 and 42 nm, respectively. The photocatalytic activity of both types of particles was tested against the sunlight-driven methylene blue (MB) degradation, and superior MB degradation was observed in the case of precipitation Al2O3 NPs (91.6 %) as compared to sol–gel Al2O3 ones (85%) within 4 h.