Insights into the coke deposited on HZSM-5, Hβ and HY zeolites during the cracking of polyethylene

Hierarchically structured ZSM-5 obtained by desilication as new catalyst for DME synthesis from methanol

“…The most active acid centers are present in conventional ZSM-5. The catalytic efficiency of acid sites decreased together with an increase in duration of alkali treatment [43][44][45][46]. Thus, we can suppose that the catalytic activity of acid sites diminished after desilication (disturbed crystalline structure).…”

Combined desilication and phosphorus modification for high-silica ZSM-5 zeolite with related study of hydrocarbon cracking performance

“…The difference could be attributed to the difference in coke formation mechanism and coke precursor [45]. The channel sizewas proved to affect the coke formation mechanism such as in the condensation reaction of aromatic rings [46]. The mesoporousity introduced by the desilication favored the formation of larger coke molecules, giving rise to a higher decomposition temperature of coke.…”

Nature and Location of Carbonaceous Species in a Composite HZSM-5 Zeolite Catalyst during the Conversion of Dimethyl Ether into Light Olefins

“…Figure 4a shows the results of FTIR-TPO profiles, determined in a single run, of the species deposited on the catalyst at 325 °C. The MS spectrometry has been used to track the CO2 signal and the FTIR spectroscopy has been used to analyze the derivative of absorbance bands (dA/dt) of four groups of species trapped on the catalyst [48][49][50]: -CH3 at 2960 cm −1 ; -CH2 and -CH at 2930 cm −1 ; conjugated double bonds in dienes or aromatics at 1610 cm −1 ; condensed aromatics at 1580 cm −1 .…”