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CO2 utilisation is becoming an appealing topic in catalysis science due to the urgent need to deal with greenhouse gases (GHG) emissions. Herein, the dry reforming of methane (DRM) represents a viable route to convert CO2 and CH4 (two of the major GHG) into syngas, a highly valuable intermediate in chemical synthesis. Nickel-based catalysts are economically viable materials for this reaction, however they show inevitable signs of deactivation. In this work stabilisation of Ni in a pyrochlore-perovskite structure is reported as a viable method to prevent fast deactivation. Substitution of Zirconium by Ni at various loadings in the lanthanum zirconate pyrochlore La2Zr2O7 is investigated in terms of reactant conversions under various reaction conditions (temperature and space velocity). XRD analysis of the calcined and reduced catalysts showed the formation of crystalline phases corresponding to the pyrochlore structure La2Zr2-xNixO7-δ and an additional La2NiZrO6 perovskite phase at high Ni loadings. Carbon formation is limited using this formulation strategy and, as a consequence, our best catalyst shows excellent activity for DRM at temperatures as low as 600 °C and displays great stability over 350 h of continuous operation. Exsolution of Ni from the oxide structure, leading to small and well dispersed Ni clusters, could explain the enhanced performance. Financial support for this work was provided by the Department of Chemical and Process Engineering of the University of Surrey and the EPSRC grants EP/J020184/2 and EP/R512904/1 as well as the Royal Society Research Grant RSGR1180353. Authors would also like to acknowledge the Ministerio de Economía, Industria y Competitividad of Spain (Project MAT2013-45008-P).

Preferential oxidation of CO in excess hydrogen (PROX) was studied over Pt catalysts supported on multi-wall carbon nanotubes in the temperature range between room temperature and the temperature of the water–gas shift unit (∼473 K). Experimental results show that the Pt/CNT catalyst exhibit a superior performance in terms of catalytic activity and selectivity towards CO 2 formation compared to a Pt/AC catalyst prepared under similar conditions. Apparently, preferential CO oxidation in excess hydrogen over Pt nanoparticles supported on carbon materials is a particle size dependent reaction, i.e. larger particles exhibit higher activity and selectivity. In any case, the incorporation of oxygen functionalities to the carbon support becomes detrimental for the CO oxidation reaction independently of the carbon support used. Finally, CeO 2 addition to the Pt/CNT catalyst further improves both catalytic activity and selectivity at low temperatures (CO conversion rate of 46% at 313 K), the catalytic performance being superior to that exhibited by a traditional PROX catalyst such as Pt/CeO 2 .

Several catalysts of cerium oxide highly dispersed on activated carbon were prepared varying the cerium precursor, the solvent and the chemical surface properties of the support, and characterized by several techniques. Afterwards, these materials were investigated as ozonation catalysts for the mineralization of two organic compounds (oxalic acid and aniline). The ozonation results were compared with those obtained in the absence of catalyst and in the presence of the parent activated carbons used for the preparation of these materials. The prepared catalysts have better performances than the parent activated carbons, denoting a clear synergic effect between activated carbon and cerium oxide. The efficiency of the catalysts is mainly affected by the amount of Ce 3+ species on the surface. However, in the ozonation of oxalic acid, the specific surface area and metal oxide particle diameter also played an important role. The use of activated carbon as support favors the removal of both organic compounds studied. Highly dispersed cerium oxide on activated carbon shows better catalytic performance than a composite with the same composition.

Titania nanoparticles have been deposited on inert porous silica supports with high specific surface area. These materials have potential applications in paint and textile industry as the titania particles selectively deposited on the inner surface of the silica supports act as a photocatalyst. The inert external surface is necessary to avoid photodegradation of the textile material or the paint components. The photocatalytic activity of the catalysts has been evaluated with two catalytic setups. One setup in aqueous phase, for the degradation of dyes such as rhodamine-6G, is commonly used. The second setup is a continuous flow gaseous phase setup which was used for the mineralization of ethanol as a representative volatile organic compound (VOC). The influence of the porosity and the morphology of the silica supports on the photocatalytic activity are discussed.