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The structure and catalytic properties of Pd catalyst supported on the outer surface or inner surface of carbon nanotubes (CNTs) have been investigated by using various experimental techniques combined with acetylene selective hydrogenation tests. It has been shown that Pd/CNTs-out catalyst exhibits higher ethylene selectivity than Pd/CNTs-in catalyst for acetylene selective hydrogenation. The electron interaction between CNTs support and palladium particles is responsible for higher ethylene selectivity over Pd/CNTs-out catalyst. Graphical Abstract: It is found that Pd/CNTs-out catalyst exhibits higher ethylene selectivity than Pd/CNTs-in catalyst for acetylene selective hydrogenation. The electron interaction between CNTs support and palladium particles is responsible for higher ethylene selectivity over Pd/CNTs-out catalyst.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The as-synthesized molybdenum nitrides and carbide has higher conversion of alkadienes and selectivity of alkenes for selective hydrogenation of longer chain alkadienes (C10–C13) than the supported palladium catalyst used in industry at higher temperature and pressure. The introduction of oxygen element to the surface of molybdenum nitride or carbide is favorable to improvement of selectivity of alkenes. The passivated molybdenum nitride or carbide catalyst pretreated in H2 at 450 °C has higher yield of alkenes than corresponding unpassivated and passivated molybdenum nitride or carbide, respectively. It was proved by XPS that the modification of molybdenum nitride or carbide by oxygen results in the change of oxidation states of molybdenum and their content. Decreasing of Mo0 content and improvement of Mo2+ and Mo3+ are favorable to the elevation of selectivity of alkenes. [Copyright &y& Elsevier]

In situ EPR investigation by using CO as probe molecules shows that even pre-reduced by H2 at lower temperature results in SMSI for anatase titania supported palladium catalyst, but not for rutile titania supported palladium catalyst. The reason of the different behavior between rutile and anatase titania supported palladium catalyst is discussed. The very different catalytic properties between anatase and rutile titania supported palladium catalyst pre-reduced at lower temperature, and the rapid change of conversion and selectivity of titania supported palladium catalyst with the elevation of pre-reduction temperature further confirm the above-mentioned results. [Copyright &y& Elsevier]

A novel magnetically separable mesoporous silica‐supported palladium catalyst was designed and prepared for the selective hydrogenation of naphthalene to tetralin, which is an important transformation from a practical viewpoint. In the catalyst, Pd nano grains were dispersed uniformly and protected within the mesoporous silica shells being coated on the Fe3O4 core, so that the durability of the catalyst could be significantly improved. [ABSTRACT FROM AUTHOR]