Non‐oxidative Coupling of Methane to Ethylene Using Mo₂C/[B]ZSM‐5

Abstract

Methane non-oxidative coupling to ethylene was investigated on Mo C/[B]ZSM-5 catalyst at 923 K and atmospheric pressure. In contrast to Mo C/[Al]ZSM-5 catalysts for methane aromatization, this material exhibits very high ethylene selectivity (>90 %) and low aromatics (benzene and naphthalene) selectivity. The much weaker Brønsted acidity of [B]ZSM-5 leads to a slow rate of ethylene oligomerization. The stability of the catalyst is greatly enhanced with 93 % of the initial reaction rate remaining after 18 h of time on stream. In-situ UV/VIS spectra indicate that prior to carburization, mono/binuclear Mo oxides are initially well dispersed onto the zeolite support. Mo carbides clusters, formed during carburization with methane, appear similar to clusters formed in [Al]ZSM-5, as indicated by the X-ray Absorption Spectroscopy (XAS) data.

Nonoxidative methane activation, coupling, and conversion to ethane, ethylene, and hydrogen over Fe/HZSM‐5, Mo/HZSM‐5, and Fe–Mo/HZSM‐5 catalysts in packed bed reactor

“…Formation rate of carbon products was 2.5 mmol of C/((mol of Pt) s), which is similar to Mo/HZSM‐5 catalyst . Lower acidity of zeolite support for Mo catalyst was also utilized by Sheng et al to shift the selectivity from aromatics toward ethylene . They used the same structure‐type zeolite as HZSM‐5 but lowered the acidity by incorporation of boron atoms in the framework instead of aluminium.…”

“…11 Lower acidity of zeolite support for Mo catalyst was also utilized by Sheng et al to shift the selectivity from aromatics toward ethylene. 13 They used the same structure-type zeolite as HZSM-5 but lowered the acidity by incorporation of boron atoms in the framework instead of aluminium. Synthesized support ([B]ZSM-5) was impregnated with 2% of Mo and tested for activity at 700 • C for 18 hours.…”

Supramolecular Organization in Confined Nanospaces

“…[236][237][238] The change of B coordination from tetrahedral to trigonal leads to interruptions in the framework and is accompanied by a 10 ppm downfield shift of 11 B NMR signal, [237,239] whereas tetrahedral boron geometry is recovered upon hydration. [240][241][242] Such weaker Brønsted acidity of B-sites guarantees a high selectivity for ethylene from methane [243] and is relevant for the environmentally friendly production of styrene. [244] Aluminophosphates (ALPO) [245,246] generally have neutral framework and large pore sizes, like in VPI-5.…”

Reaction condition optimization for non-oxidative conversion of methane using artificial intelligence

“…31 Several strategies with external energy sources such as heat. 28,[32][33][34] photon, 35,36 and plasma 37,38 have been proposed to overcome this limitation.…”