Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
J Environ Sci (China). 2006;18(1):76-82.
The morphology of supported metal nanoparticles on TiO2/silical gel (TSO) and photothermal synergism were investigated for destruction of ethylene. During photocatalytic deposition of metal nanopartilces, the effects of pH and light intensity on the morphology of coated platinum, palladium, gold on TiO2/silical gel were studied. Moreover, these catalysts were characterized by TEM, UV-Vis DRS. The pH of preparing solution have strong influence on dispersion, size and sites ofPt, Pd and Au on TSO, which were controlled by the electrostatic binding of HPtCl6-, AuCl4- and TiOH2+, Pd2+ and TiO- respectively. Platinum, gold and palladium nanoparticles were uniformly highly dispersed on the titanol sites not silanol of TiO2 /silical gel under pH = 2, pH = 9.9 respectively. For the photodegradation of ethylene, they show higher photothermal efficiency than those prepared with other pH conditions under UV illumination in a non-circulating photoreactor. The optimum weight loadings of Pt, Au, and Pd were 0.25 wt%, 0.5 wt%, 1 wt%, respectively. The synergistic effect enhanced ethylene removal and CO2 production. These results verify that the best photothermal synergistic effect depends on the dispersion, size of noble metal nano-particles. FTIR analyses of the used Pt-, Pd-TSO catalysts indicated that no significant by-products were accumulated on the surface of the catalysts, leading to them longer lifetime.
研究了负载在 TiO2 /硅凝胶（TSO）上的金属纳米粒子的形态及其光热协同作用对乙烯破坏的影响。在金属纳米粒子的光催化沉积过程中，研究了 pH 值和光强对涂覆在 TiO2 /硅凝胶上的铂、钯、金形态的影响。此外，还通过 TEM、UV-Vis DRS 对这些催化剂进行了表征。制备溶液的 pH 值对 Pt、Pd 和 Au 在 TSO 上的分散性、粒径和位置有很强的影响，这是由 HPtCl6-、AuCl4-和 TiOH2+、Pd2+和 TiO-的静电结合分别控制的。在 pH = 2 和 pH = 9.9 下，铂、金和钯纳米粒子均匀地高度分散在 TiO2 /硅凝胶的钛醇位上，而不是硅醇位上。对于乙烯的光降解，在非循环光反应器中，在 UV 照射下，它们在比其他 pH 条件下制备的催化剂具有更高的光热效率。Pt、Au 和 Pd 的最佳负载量分别为 0.25wt%、0.5wt%和 1wt%。协同效应增强了乙烯的去除和 CO2 的生成。这些结果证实，最佳的光热协同效应取决于贵金属纳米粒子的分散性和粒径。用过的 Pt-、Pd-TSO 催化剂的 FTIR 分析表明，催化剂表面没有积累明显的副产物，从而延长了它们的使用寿命。
