Nano-scale insights regarding coke formation in zeolite SSZ-13 subject to the methanol-to-hydrocarbons reaction
Sophie H. van Vreeswijk, Matteo Monai, Ramon Oord, Joel E. Schmidt, Eelco T. C. Vogt, Jonathan D. Poplawsky, Bert M. Weckhuysen
Abstract
UV-vis spectroscopy and microscopy. Radial distribution function analysis (RDF) of the APT data revealed short carbon-carbon length scale affinities, consistent with the formation of larger aromatic molecules (coke species). Using nearest neighbor distribution (NND) analysis, an increase in the homogeneity of carbon was found with increasing time-on-stream. However, carbon clusters could not be isolated due to spatial noise and limited clustering. Therefore, it was found that the coke formation in zeolite SSZ-13 (CHA) is reasonably homogeneous on the nano-scale, and is rather similar to the silicoaluminophosphate analogue SAPO-34 (CHA) but different in nano-scale coking behavior compared to previously studied zeolite ZSM-5 (MFI).