Preparation and Characterization of Multi-Component Catalysts for the Oxidative Coupling of Methane

Abstract

A multi-component catalyst Na-Mn-Zr-W-S-P/SiO₂ is prepared and tested in a fixed-bed microreactor without inert gases as thinners. The average methane conversion and the C₂ hydrocarbon selectivity in the oxidative coupling of methane are about 35 and 70 %, respectively. The yield of C₂ hydrocarbon is more than 25 %. The catalysts are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and scanning electron microscopy. Mn₂O₃ is suggested to be the main active species in the catalysts, while the addition of Zr further activates the methane molecules. The addition of W and P efficiently improves C₂ selectivity and inhibits deep-oxidation of SiO₂. Sodium easily combines with WO₄.