Pt/CeO 2 catalysts with different support shapes and prereduction temperatures were prepared and tested in the liquidphase hydrogenation of nitrobenzene. Detailed characterizations reveal that the support shape effect of Pt/CeO 2 catalysts on nitrobenzene hydrogenation originates from the exposed crystal planes on CeO 2 with different reducibilities. A high-energy surface is readily reduced to generate more Ce 3+ surface sites and oxygen vacancies, not only favoring the dispersion and stabilization of Pt species due to stronger metal−support interaction but also providing more adsorption sites for reactants and intermediates. Reduction treatment at high temperatures has been proved to be an effective way to improve the performance of Pt/CeO 2 catalysts by providing additional Ce 3+ surface sites and high H-spillover capability. The additional Ce 3+ far away from Pt, derived from a high-temperature reduction, can adsorb the N-phenylhydroxylamine intermediate more effectively due to its stronger electron-donating ability and in turn promote aniline formation. It is also found that Na ions with suitable content facilitate the generation and stabilization of surface Ce 3+ by charge transfer and help Pt particles to maintain a smaller size. Consequently, a 0.25 wt % Pt catalyst, supported on Na-containing CeO 2 nanorods and reduced at 600 °C, displays a high level of aniline productivity of 40.8 mol AN /g Pt /h and excellent stability in nitrobenzene hydrogenation at room temperature. A pathway of nitrobenzene hydrogenation catalyzed by Pt/CeO 2 is also proposed.

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A nanocube enclosed by {100} facets is the most active, residual PVP and halogen ions occupy partial surface sites.

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Manganese oxides have wide application in ambient decomposition of ozone, and their activities are affected by many parameters. Morphology engineering and metal doping are one of the effective methods to...