Yan Wenfu, Mahurin Shannon M, Pan Zhengwei, Overbury Steven H, Dai Sheng
Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
J Am Chem Soc. 2005 Aug 3;127(30):10480-1. doi: 10.1021/ja053191k.
The surfaces of TiO2 nanocrystals were modified with amorphous aluminum-oxide layers using a surface sol-gel process to control the interaction between supports and metal particles. Ultrastable Au nanocatalysts were prepared by the deposition of Au nanoparticles on the surface-modified TiO2 nanocrystals using a deposition-precipitation (DP) method. The TEM analysis showed that the Au nanoparticles on the surface-modified nanocrystal supports were highly stable with a sinter-resistant capability during high-temperature calcination. The HRTEM analysis revealed that the surface of the TiO2 nanocrystals was covered by an amorphous aluminum-oxide layer and the Au nanoparticles were primarily anchored to this amorphous layer. This amorphous aluminum-oxide layer played an extremely important role in the stabilization of the supported Au nanoparticles without affecting catalytic activities. The surface modification of nanocrystal supports highlights new opportunities in tailoring the stability and activity of supported nanocatalyst systems.
采用表面溶胶-凝胶法，用非晶态氧化铝层对TiO₂纳米晶体表面进行改性，以控制载体与金属颗粒之间的相互作用。通过沉积沉淀（DP）法将金纳米颗粒沉积在表面改性的TiO₂纳米晶体上，制备了超稳定的金纳米催化剂。透射电子显微镜（TEM）分析表明，表面改性纳米晶体载体上的金纳米颗粒高度稳定，在高温煅烧过程中具有抗烧结能力。高分辨率透射电子显微镜（HRTEM）分析显示，TiO₂纳米晶体表面覆盖有非晶态氧化铝层，金纳米颗粒主要锚定在该非晶态层上。这种非晶态氧化铝层在负载型金纳米颗粒的稳定化过程中发挥了极其重要的作用，而不影响催化活性。纳米晶体载体的表面改性为定制负载型纳米催化剂体系的稳定性和活性带来了新的机遇。
