Cobalt Oxide Catalysts on Commercial Supports for N sub(2)O Decomposition

Co sub(3)O sub(4) oxide catalysts prepared on different commercial supports, namely, TiO sub(2), Al sub(2)O sub(3), and Mg-Al mixed oxides with various Mg and Al concentrations, were characterized by atomic absorption spectrometry, Brunauer-Emmett-Teller method, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and H sub(2) temperature-programmed reduction, tested for N sub(2)O decomposition, and compared with bulk Co sub(3)O sub(4). In spite of the fact that Co sub(3)O sub(4)/70Mg30Al also contained hardly reducible compounds, it possessed the highest catalytic activity, probably due to the presence of active sites with easier reducibility and better dispersion of the active phase on the support contributing to a higher number of active sites. The conversion over Co sub(3)O sub(4)-supported tablets is comparable with that of the same catalyst bed of bulk Co sub(3)O sub(4) tableted catalyst. Cobalt-based catalysts exhibit excellent activities for the decomposition of N sub(2)O, a pollutant contributing to the greenhouse effect. Difficulties in the formation of Co sub(3)O sub(4) can be circumvented by supporting the active cobalt spinel phase on an appropriate support. Co sub(3)O sub(4) oxide catalysts prepared on different commercial supports with various Mg and Al concentrations are characterized aiming at a catalyst for industrial application.