Comparison of oxidizing agents for the oxidative coupling of methane over state-of-the-art catalysts

Abstract

The synthesis of selected state-of-the-art catalysts providing high performances in the oxidative coupling of methane (OCM) with O2 was reproduced according to the respective recipes reported in literature. A reference material with identical stoichiometric composition was further synthesized by applying the cellulose templating method. This method increases the surface area and affects the phase composition and crystallite size of the catalysts as determined by N2-physisoprtion, X-ray diffraction and scanning electron microscopy. This, however, is in most cases detrimental to the catalytic OCM performance due to enhanced global activity resulting in hot spots in the catalyst bed. Catalysts were tested in the OCM under variation of temperature (973–1073 K), GHSV (3600–100,000 h−1) and oxidizing agent (O2 and N2O). In general, conversions of CH4 when using N2O are lower than in the presence of O2, however, the selectivities to C2 products ethane and ethylene are higher even at a similar level of CH4 conversion. This confirms the presence of different oxygen species formed by activation of these oxidizing agents

Alternative Oxidants for the Catalytic Oxidative Coupling of Methane

“…More recently, a 2012 publication from Schomäcker et al. compared the OCM performance of a series of literature catalysts and catalysts prepared via cellulose templating (CT) using both N 2 O and O 2 as oxidants [20b] . The CT synthesis method had previously been applied to perovskite O 2 ‐OCM catalysts in order to cheaply produce bulk materials with high surface area [21] .…”

Methane Coupling to Ethylene and Longer-Chain Hydrocarbons by Low-Energy Electrical Discharge in Microstructured Reactors

“…1,7,8 Specifically, general trends of methane conversion and C 2+ product selectivity reported in the literature suggest that catalysts that enable high methane conversion have low selectivity towards C 2+ hydrocarbons and generate increasing amounts of CO/CO 2 , while high selectivity to C 2+ hydrocarbons catalysts show relatively low methane conversions. 9,10 As a result, research efforts have begun focusing on alternative processing methods for the chemical conversion of methane, and methods employing electrically generated nonthermal plasmas are notable. 11 Nonthermal plasmas simply refer to plasmas in which the energy distribution of the free electrons is much higher than that of atomic and molecular ions and neutral species.…”

Heterogeneous catalyst discovery using 21st century tools: a tutorial

“…17,18 This tutorial focuses on empirical modelling methods, illustrating them with three case studies: rst, we discuss statistical experimental design on the oxidative coupling of methane. This chemistry is receiving an increased amount of attention in both academia and industry 19,20 with the expected price developments for methane resulting from shale gas production. Then, we review the use of exploratory data analysis with principal component analysis (PCA) and descriptor-performance relationships using hydrogenation of 5-ethoxymethylfurfural (EMF).…”