Low-temperature catalytic oxidation of vinyl chloride over Ru modified Co3O4 catalysts
Abstract
Ruthenium modified cobalt oxides were prepared by (1) impregnating ruthenium chloride hydrate on cobalt oxides, Ru-supported catalysts (Ru/Co3O4), and (2) Ru-doped catalysts (Ru–Co3O4) where the ruthenium ions were added to the precursor solution, by a one-step sol–gel method with cobalt nitrate. The physicochemical properties of the catalysts were characterized by ICP, BET, XRD, HR-TEM, TPR, and XPS analysis. The effects of ruthenium were studied for the total oxidation of vinyl chloride. This Ru modifier was observed to enhance oxygenate formation. The different preparation methods made contributions to the different amounts of Ru4+ on the surfaces of the catalysts while Ru4+ would be in synergy with Co2+ concentration, and this also changed the chemical coordination of oxygen on the surface. Dispersion of Ru oxides on the cobalt oxides surface could not only improve the catalytic activity and stability on steam, but also decrease the amount of chlorinated by-products and increase HCl selectivity.