3D geometric modeling analysis of contact probability effect in carbon black oxidation over MnOx-CeO2 catalysts

Abstract

MnOx-CeO2 composite catalysts have attracted interest from all over the world as promising catalysts for carbon black oxidation. The contact between carbon black and catalyst, and the surface physicochemical properties of the catalyst, are the main factors in carbon black oxidation, while the contact is a basic one affecting the ignition of the oxidation. In this work, MnOx-CeO2 catalysts with different geometric morphologies (nanorod and nanoparticle) are prepared to determine the effect of geometric morphology on the contact probability between catalysts and carbon black. Compared with the nanorod catalyst, nanoparticle catalyst is significantly advanced in catalytic activity (T10 = 314 °C, T50 = 346 °C, T90 = 383 °C) and relative contact probability (9.549, compared to the 7.639 of nanorod catalyst, according to the 3D geometric modeling). O2-TPD, H2-TPR, and In-situ UV Raman experiments reveal that the concentration of surface intrinsic oxygen vacancy of the two catalysts are approximative. The consumption of oxygen vacancy is based on the active sites provided, which is relative to the morphology. The better consumption results in better utilization of intrinsic active oxygen species in nanoparticle sample. This finding proves the correlation between contact probability and carbon black catalytic activity, and witnesses that the consumption efficiency of surface intrinsic oxygen vacancy is an initial factor in carbon black oxidation.