Well-defined ceria nanocubes covered by oleic acid with exposed {100} facets have been synthesized and exhibited exclusive selectivity for the oxidation of toluene to benzaldehydes in liquid phase by O(2).

Inorganic nanocrystals catalysts with a high proportion of high-energy surfaces can bring about high performance for catalysis and has been an important research topic in the past decades. Gamma alumina is one of the most important inorganic oxides used as solid acids or catalytic support for many more industrial catalysts. However, the preparation of gamma alumina mainly with high-energy external surfaces has never been reported because it has a complicated crystal structure. We demonstrate here in depth a new-type γ-alumina material from a systematic investigation, which is controllably synthesized as regular nanotubes with high-energy {111} facets as main external surfaces. The newtype material shows much better performance as acid catalyst or catalytic support for metals, as compared with common γalumina whose main exposed surface is stable {100} or {110} facets in irregular morphology. As an example, palladium loaded on the new-type γ-alumina is easily prepared in higher dispersion and unique electronic states upon the stronger interaction with the support, giving rise to better catalytic performance for semihydrogenation of alkynes, without any assistance of other metals. The systematic investigation should open opportunities of catalyst innovation for new chemical reactions.

A series of dealuminated mordenite (MOR) samples with different acidities and various porosities were prepared through steam treatment of H + /Na + mordenite. The obtained zeolites were elaborately characterized by X-ray diffraction, N 2 adsorption−desorption, scanning electron microscopy, 29 Si nuclear magnetic resonance (NMR), 27 Al NMR, NH 3 temperature-programmed desorption, and Fourier transform infrared spectroscopy, and the catalytic performance for dimethyl ether (DME) carbonylation was investigated. The characterization results revealed that the kind of cation balancing the zeolite charge had a great effect on the crystalline structure and acidity of mordenite zeolite during steam treatment and ion-exchange processes. Dealumination was observed both on Na-MOR and H-MOR, but it was much milder on the Na-MOR zeolite comparatively. After Na-MOR was treated with steam, its structure was wellpreserved, but side pockets of mordenite were opened, resulting in an increased microporous volume and strong acid sites. Interestingly, it was found that the removal of framework Al in the 12MR channel was favored over the 8MR channel during steaming of Na-MOR, leading to the mordenite to possess more acid sites in the 8MR channel compared with those in the 12MR channel. As for the steamed H-MOR, both the crystalline structure and porosity were obviously damaged, resulting in a decreased microporous volume and acidity. The influence was more significant in the 8MR channel of H-MOR due to the obvious removal of framework Al and blockage of side pockets. The performance tests revealed that Na-MOR treated with steam was an effective way to enhance the catalytic performance for DME carbonylation reaction. The N-773 catalyst (steamed with Na-MOR at 773 K) showed a methyl acetate product rate of 0.33 gg −1 h −1 , which was much higher than that of the parent H-MOR (0.23 gg −1 h −1 ). Moreover, the dealuminated catalyst exhibited a slow deactivation rate, which was possibly ascribed to the reduced strong acid sites in the 12MR channels. Although the steam treatment of H-MOR resulted in a lower activity in the DME carbonylation reaction, it exhibited a higher MeOAc selectivity and improved stability for its overall decreased acidity.

High quality noncrystalline NiPB nanotubes were synthesized and exhibited high efficiency for the catalytic hydrogenation of p-chloronitrobenzene due to the characteristic confinement effect of the nanotubes.

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