A series of carbide-derived carbons (CDC) have been prepared starting from TiC and using different chlorine treatment temperatures (500ºC-1200ºC). Contrary to N 2 adsorption measurements at -196ºC, CO 2 adsorption measurements at room temperature and high pressure (up to 1 MPa) together with immersion calorimetry measurements into dichloromethane suggest that the synthesized CDC exhibit a similar porous structure, in terms of narrow pore volume, independently of the temperature of the reactive extraction treatment used (samples synthesized below 1000ºC). Apparently, these carbide-derived carbons exhibit narrow constrictions were CO 2 adsorption under standard conditions (0ºC and atmospheric pressure) is kinetically restricted. The same accounts for a slightly larger molecule as N 2 at a lower adsorption temperature (-196ºC), i.e. textural parameters obtained from N 2 adsorption measurements on CDC 2 must be underestimated. Furthermore, here we show experimentally that nitrogen exhibits an unusual behavior, poor affinity, on these carbide-derived carbons. CH 4 with a slightly larger diameter (0.39 nm) is able to partially access the inner porous structure whereas N 2 , with a slightly smaller diameter (0.36 nm), does not. Consequently, these CDC can be envisaged as excellent sorbent for selective CO 2 capture in flue-gas streams.

Highlights  An alternative route using a MOF as catalyst precursor has been studied  The MOF called Cu-BTC has been used as precursor  The MOF was impregnated with cerium precursor  The impregnated MOF was pyrolyzed to obtain the catalyst  With the pyrolysis method we could control the final properties of the catalysts ABSTRACT: Herein, we have studied an alternative route for preparing CuOx/CeO2 catalysts using metal organic frameworks (MOFs) as precursors. Usually, CuOx/CeO2 materials are prepared by wet impregnation of ceria support. In this study, we have impregnated a Cu-MOF with a ceria precursor and then pyrolized the impregnated MOF using different conditions and procedures. The prepared catalysts have been characterized by using a wide range of techniques such as XRD, XPS, Raman, and TPR. We have found that the pyrolysis method determines the dispersion of the oxidized copper species on the ceria surface what, in turn, controls the catalytic activity and selectivity of the catalysts in the reverse water-gas shift (RWGS) reaction. We have compared the behavior of the MOF-derived

Porous carbon and carbide materials with different structures were characterized using adsorption of nitrogen at 77.4 K before and after pre-adsorption of n-nonane. The selective blocking of the microporosity with n-nonane shows that ordered mesoporous silicon carbide material (OM-SiC) is almost exclusively mesoporous whereas the ordered mesoporous carbon CMK-3 contains a significant amount of micropores (~25%). The insertion of micropores into OM-SiC using selective extraction of silicon by hot chlorine gas leads to the formation of ordered mesoporous carbide-derived carbon (OM-CDC) with a hierarchical pore structure and significantly higher micropore volume as compared to CMK-3, whereas a CDC material from a non-porous precursor is exclusively microporous. Volumes of narrow micropores, calculated by adsorption of carbon dioxide at 273 K, are in linear correlation with the volumes blocked by n-nonane. Argon adsorption measurements at 87.3 K allow for precise and reliable calculation of the pore size distribution of the materials using density functional theory (DFT) methods.

Graphical Abstract Highlights •Pt/CeO2-TiO2 is a better catalyst for PROX than Pt supported on pure oxides • The support is directly related with the catalyst performance

In situ high pressure 129Xe NMR spectroscopy in combination with volumetric adsorption measurements were used for the textural characterization of different carbon materials with well-defined porosity including microporous carbide-derived carbons, ordered mesoporous carbide-derived carbon, and ordered mesoporous CMK-3. Adsorption/desorption isotherms were measured also by NMR up to relative pressures close to p/p 0 = 1 at 237 K. The 129Xe NMR chemical shift of xenon adsorbed in porous carbons is found to be correlated with the pore size in analogy to other materials such as zeolites. In addition, these measurements were performed loading the samples with n-nonane. Nonane molecules preferentially block the micropores. However, 129Xe NMR spectroscopy proves that the nonane also influences the mesopores, thus providing information about the pore system in hierarchically structured materials.