TiO2 (P25)-supported Au-Pd bimetal nanoparticles displayed excellent performance in the solvent-free benzyl alcohol catalytic oxidation. However, little research attention has been paid to investigate the effects of TiO2 form on the catalytic activity of Au-Pd/TiO2. In the present research, rutile, brookite, and anatase TiO2 were successfully synthesized and subsequently applied as the carrier to load Au-Pd nanoparticles by the deposition-precipitation method. The experimental results indicated that the benzyl alcohol conversion employing the rutile TiO2-supported Au-Pd catalyst is higher than the conversion of anatase and brookite TiO2-loaded Au-Pd catalysts. However, the Au-Pd/TiO2-rutile displayed the lowest and highest selectivity toward benzaldehyde and toluene, respectively. ICP-AES, XRD, XPS, and TEM were conducted to characterize these catalysts. The corresponding experimental results revealed that the excellent performance of Au-Pd/TiO2-rutile catalyst was attributed to both the smaller Au-Pd nanoparticle size distribution and the higher concentrations of Oα and Pd2+ species on the catalyst surface. In the recycle experiments, the Au-Pd/TiO2-rutile catalyst displayed lower reaction stability compared with the Au-Pd/TiO2-anatase and Au-Pd/TiO2-brookite, which might be due to the coverage of larger amount of aldehyde products on the surface.

中文翻译：

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TiO2上沉积的Au-Pd双金属上的苄醇的无溶剂催化氧化：金红石，板钛矿和锐钛矿的比较。

TiO2（P25）负载的Au-Pd双金属纳米颗粒在无溶剂的苯甲醇催化氧化中显示出优异的性能。然而，很少有研究注意力来研究TiO 2形式对Au-Pd / TiO 2催化活性的影响。在本研究中，成功​​地合成了金红石，板钛矿和锐钛矿型TiO2，随后通过沉积沉淀法将其用作载体以负载Au-Pd纳米粒子。实验结果表明，采用金红石型TiO2负载的Au-Pd催化剂的苯甲醇转化率高于锐钛矿和负载板钛矿型TiO2的Au-Pd催化剂的转化率。然而，Au-Pd / TiO2-金红石分别显示出对苯甲醛和甲苯的最低和最高选择性。ICP-AES，XRD，XPS，进行了TEM和TEM表征这些催化剂。相应的实验结果表明，Au-Pd / TiO2-金红石催化剂的优异性能归因于较小的Au-Pd纳米粒径分布和较高的Oα和Pd2 +物种在催化剂表面的浓度。在循环实验中，Au-Pd / TiO2-金红石催化剂与Au-Pd / TiO2-锐钛矿和Au-Pd / TiO2-板钛矿相比，显示出较低的反应稳定性，这可能是由于覆盖了大量的醛产物在表面上。