Synthesis, characterization and reactivity study of nanoscale magnesium oxide

Abstract

In this study, different samples of nanoscale magnesium oxide (MgO) were synthesized using “ aqueous wet chemical method ( MgO-OX)” and “ surfactant method ( MgO-BR: surfactant used Brij 56, MgO-TR: surfactant used Triton 100-X)”. The samples were then characterized by: X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), diffuse reflectance infrared Fourier-transform (DRIFT) spectroscopy and Thermogravimetric analysis (TGA). From the analyses performed, it was noticed that the amount of hydroxyl and carbonate groups differs as a function of the synthesis procedure. The estimated dimensions of the particles are smaller in the MgO-OX sample (around 13 nm) compared to the 16 nm of the MgO-BR samples and 18 nm of the MgO-TR samples. Studies on the reactivity of MgO nanoparticles were performed using the DRIFT spectroscopy. Methanol and carbon monoxide were used to study the catalytic activity of MgO. At relatively low temperatures, methanol dissociates to methoxide species. At higher temperatures, different oxidation products (formates and formic acid, CO and CO 2) were observed to form. MgO-OX showed more oxidative properties than the MgO-TR/BR samples. Moreover, the basic and acidic sites were investigated using carbon dioxide and pyridine, respectively; the obtained results indicate a different distribution of acidic/basic sites in the different samples.