Chemically activated poly(furfuryl alcohol)-derived CMK-3 carbon catalysts for the oxidative dehydrogenation of ethylbenzene

Abstract

The surface of CMK-3 carbon, synthesized by the reversible replication of mesoporous silica (SBA-15) using poly(furfuryl alcohol) as a carbon precursor, was activated by wet oxidation with an aqueous solution of HNO 3 or H 2 O 2 . The process was performed at 50°C using solution containing different concentrations of the oxidizing agent. It was found that during the modification no significant changes in textural and structural properties of CMK-3 replica occurred. However, the treatment resulted in the formation of appreciable amounts of surface species containing oxygen. XPS and DRIFT spectroscopy allowed to identify and quantify the surface functional groups. Their stability was studied by TG-FTIR measurements. CO and CO 2 were found as main gaseous products evolved during thermal decomposition under inert atmosphere. Finally, the modified samples were tested in the catalytic oxidative dehydrogenation * Corresponding author. Tel. +48 12 6632006. Fax +48 12 6340515. E-mail address: kustrows@chemia.uj.edu.pl (P. Kuśtrowski) 2 of ethylbenzene to styrene at 350°C in the presence of oxygen as an oxidizing agent (at O 2 /ethylbenzene molar ratio of 1.0 and 3.0). At the beginning of the catalytic run, the highest styrene yield and selectivity was achieved at the lower O 2 content over the catalysts treated with nitric acid. Nevertheless, all studied catalysts underwent a gradual deactivation due to coke formation and changes in the distribution of surface moieties.

Influence of carbon precursor on porosity, surface composition and catalytic behaviour of CMK-3 in oxidative dehydrogenation of propane to propene

“…Ordered mesoporous carbon materials synthesized by various methods and pre-treated at different conditions exhibited earlier a very similar behaviour in the oxidative dehydrogenation of ethylbenzene [21]. It was found that during this process the surface oxygencontaining species generated during the synthesis and subsequent modifications were lost by decomposition and/or re-arrangement (connected with the formation of carbon deposit) and, in consequence, similar activity was observed after some hours on stream over all materials [21,23,24]. Figure 8 summarizes the variations in selectivity to propene vs. TOS.…”

Oxidative dehydrogenation of ethylbenzene over CMK-1 and CMK-3 carbon replicas with various mesopore architectures

“…soot, graphite, carbon nanofilaments [14], activated carbons [16,17], multi-walled carbon nanotubes, onion-like carbons [18,19], nanodiamonds [20]) were tested in M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 4 ODH. Among them, CMK-type materials showed a very attractive catalytic activity [8,[21][22][23].…”

Insights into the Synthesis and Surface Functionalization of Mesoporous Carbon for Catalytic Applications

“…In particular, mesoporous carbons with high surface area, ordered structure and pore dimension between 2 and 50 nm, increase the mass transfer, limited in active carbon supports . The main challenge in the application of the mesoporous carbon as metal‐free catalyst is to prepare a well ordered structure with a controlled degree of functionalization ,…”

“…[5] The main challenge in the application of the mesoporous carbon as metal-free catalyst is to prepare a well ordered structure with a controlled degree of functionalization. [6,7] The ordered mesoporous carbon structure can be obtained by the replica method, through a sacrificial templating agent that controls the order degree and the formation of mesopores. [8] The soft templating method is generally preferred to the hard templating ones.…”

“…[12][13][14] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 Post-synthesis oxidative treatments in liquid phase with HNO 3 and H 2 O 2 are well-known to create new surface functional groups in carbonaceous materials, [15] however, the composition and the morphology of the material can be altered. [6,15] The aim of this work was twofold: i) to prepare carbons with an optimized mesopore structure for catalytic applications using green chemicals; ii) to introduce surface functional groups without damaging the ordered structure giving rise to catalysts active in oxidation reactions.…”