Pt/CeO₂ catalysts with different support shapes and prereduction temperatures were prepared and tested in the liquid-phase hydrogenation of nitrobenzene. Detailed characterizations reveal that the support shape effect of Pt/CeO₂ catalysts on nitrobenzene hydrogenation originates from the exposed crystal planes on CeO₂ with different reducibilities. A high-energy surface is readily reduced to generate more Ce³⁺ 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/CeO₂ catalysts by providing additional Ce³⁺ surface sites and high H-spillover capability. The additional Ce³⁺ 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 Ce³⁺ by charge transfer and help Pt particles to maintain a smaller size. Consequently, a 0.25 wt % Pt catalyst, supported on Na-containing CeO₂ 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/CeO₂ is also proposed.

中文翻译：

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Pt / CeO ₂催化剂上硝基苯的高效加氢制苯胺：载体的形状效应和其他Ce ^3+位点的关键作用

制备了具有不同载体形状和预还原温度的Pt / CeO ₂催化剂，并在硝基苯的液相加氢中进行了测试。详细的特征表明，Pt / CeO ₂催化剂对硝基苯加氢的载体形状效应源自具有不同还原度的CeO ₂上暴露的晶面。高能表面很容易还原以生成更多的Ce ³⁺表面位点和氧空位，不仅由于金属与载体之间更强的相互作用而有利于Pt物种的分散和稳定，而且还为反应物和中间体提供了更多的吸附位点。通过提供额外的Ce ³⁺表面位点和高H溢出能力，高温还原处理已被证明是提高Pt / CeO ₂催化剂性能的有效方法。高温还原产生的远离Pt的额外Ce ³⁺可以吸附N-苯基羟胺中间体由于其更强的给电子能力而更有效，进而促进了苯胺的形成。还发现具有合适含量的Na离子通过电荷转移促进表面Ce ³⁺的产生和稳定化，并帮助Pt颗粒保持较小的尺寸。因此，负载在含Na的CeO ₂纳米棒上并在600°C下还原的0.25 wt％Pt催化剂显示出40.8 mol _AN / g _Pt / h的高苯胺生产率，并且在室温下硝基苯加氢中具有出色的稳定性。还提出了Pt / CeO ₂催化硝基苯加氢的途径。