Elucidation of high activity and reaction mechanism for 1,2-dichloroethane catalytic oxidation over CoMnOx/HZSM-5 catalyst

Abstract

The preparation of catalysts with excellent catalytic activity and stability in the catalytic oxidation of CVOCs by a simple and economical method with suitable support remained a challenge. For this reason, the MnCoO_x/HZ-x catalysts prepared by impregnation method with different Si/Al ratios of HZSM-5 as the support, and applied to the catalytic combustion of 1,2-dichloroethane (1,2-DCE). The results confirmed that the Si/Al ratio of the carrier affected the physicochemical properties of the surface active species, which improved the catalytic activity. The excellent catalytic activity (T₉₀ = 193 °C) and stability of MnCoO_x/HZ-25 were attributed to the abundance of Mn⁴⁺, Co²⁺, and surface adsorbed oxygen, the good redox capacity, and the suitable acidic strength stimulated by the lower Si/Al ratio of the carrier. In situ DRIFTS verified that at high temperatures and in the presence of oxygen, the production of vinyl alcohol or vinyl chloride species was not favored, and oxygenated intermediates such as carboxylates were mainly produced on MnCoO_x/HZ-25.