Understanding the Deactivation Phenomena of Small-Pore Mo/H-SSZ-13 during Methane Dehydroaromatisation.

Small pore zeolites have shown great potential in a number of catalytic reactions. While Mo-containing medium pore zeolites have been widely studied for methane dehydroaromatisation (MDA), the use of small pore supports has drawn limited attention due to the fast deactivation of the catalyst. This work investigates the structure of the small pore Mo/H-SSZ-13 during catalyst preparation and reaction by operando X-ray absorption spectroscopy (XAS), in situ synchrotron powder diffraction (SPD), and electron microscopy; then, the results are compared with the medium pore Mo/H-ZSM-5.

X-ray diffraction computed tomography studies examining the thermal and chemical stabilities of working BaSrCoFeO membranes during oxidative coupling of methane.

In this study we present the results from two in situ X-ray diffraction computed tomography experiments of catalytic membrane reactors (CMRs) using Ba0.5Sr0.5Co0.

Catalytic decomposition of NO over Cu-Al-O mixed metal oxides.

Cu-Al-O mixed metal oxides with intended molar ratios of Cu/Al = 85/15, 78/22, 75/25, 60/30, were prepared by thermal decomposition of precursors at 600 °C and tested for the decomposition of nitrous oxide (deNO). Techniques such as XRD, ICP-MS, N physisorption, O-TPD, H-TPR, FT-IR and XAFS were used to characterize the obtained materials. Physico-chemical characterization revealed the formation of mixed metal oxides characterized by different specific surface area and thus, different surface oxygen default sites.

Operando Spectroscopic Studies of Cu-SSZ-13 for NH-SCR deNOx Investigates the Role of NH in Observed Cu(II) Reduction at High NO Conversions.

The small pore zeolite chabazite (SSZ-13) in the copper exchanged form is a very efficient material for the selective catalytic reduction by ammonia (NH) of nitrogen oxides (NOx) from the exhaust of lean burn engines, typically diesel powered vehicles. The full mechanism occurring during the NH-SCR process is currently debated with outstanding questions including the nature and role of the catalytically active sites. Time-resolved operando spectroscopic techniques have been used to provide new level of insights in to the mechanism of NH-SCR, to show that the origin of stable Cu(I) species under SCR conditions is potentially caused by an interaction between NH and the Cu cations located in eight ring sites of the bulk of the zeolite and is independent of the NH-SCR of NOx occurring at Cu six ring sites within the zeolite.