Cu and Mn oxides supported on urea-modified HZSM-5 catalysts for the catalytic oxidation of toluene

Series of ZSM-5 molecular sieve-loaded cobalt-based catalysts (Co/S-0.1, CoCu/S-0.1, CoMn/S-0.1) were prepared using the impregnation method. The impact of calcination temperature and loading on the catalytic activity of cobalt-based catalysts for the oxidation of toluene was examined. The experimental results showed that the loading of 10wt% Co demonstrated notable catalytic activity following calcination at 300℃ (T ₉₀ =258.26℃). The impact of manganese and copper supplementation on the oxidative capacity of cobalt-based catalysts for the catalytic oxidation of toluene was evaluated through a comparative analysis. The catalytic activity of the series of catalysts for toluene demonstrated the following order Co _0.75 Cu _0.25 /S-0.1>Co/S-0.1>Co _0.75 Mn _0.25 /S-0.1> Mn/S-0.1>Cu/S-0.1. The incorporation of copper significantly enhanced the catalytic activity of the cobalt-based catalysts, the catalytic performance of Co _0.75 Cu _0.25 /S-0.1 catalyst (T ₉₀ =238.65℃) in toluene oxidation was significantly better than that of Co/S-0.1 (T ₉₀ =258.26℃). X-ray photoelectron spectroscopy (XPS) analysis of the cobalt-based catalysts showed that Co _0.75 Cu _0.25 /S-0.1 contained a large amount of Co ³⁺ and Cu ⁺ . After Cu doping of Co-based catalysts, the increase in Co ³⁺ and Cu ⁺ content promotes the generation of active oxygen vacancies on the surface of the catalysts, which is the key to enhancing the performance of the catalysts.