Camposeco Roberto, Zanella Rodolfo
Instituto de Ciencias Aplicadas Y Tecnología, Universidad Nacional Autónoma de México, Circuito Exterior S/N, C. U., 04510, Mexico City, Mexico.
Environ Sci Pollut Res Int. 2022 Nov;29(51):76992-77006. doi: 10.1007/s11356-022-21076-2. Epub 2022 Jun 8.
The present work highlights the versatility of a TiO-AlO mixed oxide bearing highly dispersed gold nanoparticles that was applied in the CO oxidation reaction at room temperature. The TiO, AlO, and TiO-AlO supports were synthesized by the sol-gel method, while gold nanoparticles were added by the deposition-precipitation with urea method using a theoretical Au loading of 2 wt.%. A promotional effect of the TiO-AlO support on the activity of gold catalysts with respect to TiO and AlO was observed; Au/TiO-AlO showed outstanding CO oxidation, being active from 0 °C and stable throughout a 24-h test. As for the alumina content (5, 10, and 15 wt.%) in TiO, it improved the textural properties by retarding the crystal growth and anatase-rutile phase transformation of TiO, suppressing the deposition of carbon on the catalyst surface and stabilizing the Au nanoparticles even at high temperatures. Gold was highly dispersed with nanoparticle sizes ranging from 1 to 2 nm when H was used to treat thermally the Au/TiO-AlO, Au/TiO and Au/AlO materials. In addition, the XPS technique helped elicit that Au and Au boosted their interaction with the TiO, AlO, and TiO-AlO supports by means of charge transfer, which resulted in outstanding CO oxidation activity from 0 °C. Likewise, the key factors that control the peculiar catalytic performance in the CO oxidation reaction are discussed, which represents a step forward in the versatility behavior of gold catalysts supported on mixed oxide catalysts.
本工作突出了负载高度分散金纳米颗粒的TiO-AlO混合氧化物在室温下CO氧化反应中的多功能性。TiO、AlO和TiO-AlO载体通过溶胶-凝胶法合成，而金纳米颗粒通过尿素沉积沉淀法添加，理论金负载量为2 wt.%。观察到TiO-AlO载体对金催化剂相对于TiO和AlO活性的促进作用；Au/TiO-AlO表现出出色的CO氧化性能，在0°C下具有活性，并在24小时测试中保持稳定。至于TiO中氧化铝的含量（5、10和15 wt.%），它通过延缓TiO的晶体生长和锐钛矿-金红石相转变改善了织构性质，抑制了碳在催化剂表面的沉积，甚至在高温下也能稳定金纳米颗粒。当用H对Au/TiO-AlO、Au/TiO和Au/AlO材料进行热处理时，金高度分散，纳米颗粒尺寸在1至2nm范围内。此外，XPS技术有助于揭示Au和Au通过电荷转移增强了它们与TiO、AlO和TiO-AlO载体的相互作用，这导致了从0°C起就具有出色的CO氧化活性。同样，讨论了控制CO氧化反应中特殊催化性能的关键因素，这代表了混合氧化物催化剂负载的金催化剂多功能行为研究的一大进步。
