Picrasma quassioides mediated cerium oxide nanostructures and their post-annealing treatment on the microstructural, morphological and enhanced catalytic performance

Abstract Cerium oxide (CeO 2 ) nanostructures are an interesting metal oxide in catalysis owing to their unique redox properties and high mobility of oxygen vacancies at the surface. CeO 2 nanostructure was synthesized via a green route using an aqueous extract of Picrasma quassioides bark. Formation of ceria nanostructures were monitored by UV–vis absorption spectroscopy and Fourier transform infrared spectroscopy (FTIR). Annealing temperature-dependent crystallite size and lattice strain on the X-ray peak broadening of the CeO 2 nanostructures was determined by the size–strain plots. The application of the green synthesized CeO 2 nanostructures for the catalytic degradation of methylene blue by NaBH 4 was carried out. We demonstrated that the catalytic decomposition rate was gradually improved due to the increase of annealing temperature of CeO 2 nanostructure, and obtained highest performance at 600 °C annealed sample. This is because of the significantly improved crystallinity of CeO 2 nanostructure at higher temperature, leading in a low density of crystalline defects and wide distribution of nanostructure with a large surface area to provide more active electrons (e − ) for the decomposition of dye.