Hydrogen‐Permeable Tubular Membrane Reactor: Promoting Conversion and Product Selectivity for Non‐Oxidative Activation of Methane over an Fe©SiO₂ Catalyst

Abstract

Non-oxidative methane conversion over FeSiO 2 catalyst was studied for the first time in ah ydrogen (H 2 ) permeable tubular membrane reactor.T he membrane reactor is composed of am ixed ionic-electronic SrCe 0.7 Zr 0.2 Eu 0.1 O 3Àd thin film ( % 20 mm) supported on the outer surface of ao neend capped porous SrCe 0.8 Zr 0.2 O 3Àd tube.Significant improvement in CH 4 conversion was achieved upon H 2 removal from the membrane reactor compared to that in afixed-bed reactor. The FeSiO 2 catalyst in the H 2 permeable membrane reactor demonstrated astable % 30 %C 2+ single-pass yield, with up to 30 %CH 4 conversion and 99 %selectivity to C 2 (ethylene and acetylene) and aromatic (benzene and naphthalene) products, at the tested conditions.The selectivity towardsC 2 or aromatics was manipulated purposely by adding H 2 into or removing H 2 from the membrane reactor feed and permeate gas streams.

Direct experimental detection of hydrogen radicals in non-oxidative methane catalytic reaction

“…The recently reported non-oxidative methane conversion to olefins, aromatics and hydrogen (MTOAH) over the single iron sites embedded in a silica matrix (Fe©SiO 2 ) does avoid complete dehydrogenation to coke and over-oxidation to CO 2 , representing an atom-economic transformation process of methane [ 18 , 19 ]. Thereafter, similar single sites of catalysts were reported [20][21][22][23] . For example, Sakbodin et al studied the MTOAH over Fe©SiO 2 in a hydrogen permeable tubular membrane reactor for the first time and 20% methane conversion with 65% C 2 selectivity was obtained at 1303 K for 60 h [20] .…”

“…Thereafter, similar single sites of catalysts were reported [20][21][22][23] . For example, Sakbodin et al studied the MTOAH over Fe©SiO 2 in a hydrogen permeable tubular membrane reactor for the first time and 20% methane conversion with 65% C 2 selectivity was obtained at 1303 K for 60 h [20] . Xie et al also reported that methane can be activated by single-atom Pt dispersed within ceria support (Pt@CeO 2 ) under non-oxidative conditions, achieving 14.4% methane conversion with 74.6% selectivity toward C 2 products at 1248 K [21] .…”

Innovative steam methane reforming for coproducing CO‐free hydrogen and syngas in proton conducting membrane reactor

“…In this work, by coupling steam methane reforming with in‐situ H 2 removal in a proton conducting membrane reactor, the coke deposition is expected to be inhibited in the presence of steam on methane side. In fact, when using proton conducting membrane to replace oxygen‐permeable membrane, the reaction on methane side changes from POM to SMR that is more coke‐resistant, and also a mature commercial process. After 100 hr reaction, temperature programmed oxidation (TPO) and thermogravimetric analysis (TGA) were used to characterize the spent catalyst (Figure S3).…”

“…First, methane and water are sent to the feed side of the membrane. At high temperatures, steam methane reforming (SMR) takes place over Ni‐based catalyst packed on the membrane surface, forming syngas with a H 2 /CO ratio of 3 according to CH 4 + H 2 O → 3H 2 + CO. Then, the produced hydrogen molecules can chemically adsorb and dissociate into protons (H + ) on membrane surface, which can be further in‐situ removed as H + to the other side if there is a gradient of hydrogen partial pressure across the dense proton conducting membrane . Meanwhile, the electrons migrate in the same direction to maintain the local charge neutrality.…”

Metal Catalysts for Heterogeneous Catalysis: From Single Atoms to Nanoclusters and Nanoparticles

“…The concept of Fe@SiO 2 catalyst has further been applied for nonoxidative activation of CH 4 in hydrogen-permeable tubular membrane reactor. 145 By adding H 2 in the feed gas into the membrane reactor, 30% conversion of CH 4 and 99% selectivity to C2 products (acetylene and ethylene) can be achieved with good stability at 1303 K.…”