Catalytic benzene oxidation by biogenic Pd nanoparticles over 3D-ordered mesoporous CeO2
Catalytic benzene oxidation by biogenic Pd nanoparticles over 3D-ordered mesoporous CeO2
复制标题
生物源 Pd 纳米粒子在 3D 有序介孔 CeO2 上催化苯氧化
DOI：
10.1016/j.cej.2019.01.012
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发表时间：
2019-04-15
影响因子：
15.1
通讯作者：
Li, Qingbiao
中科院分区：
文献类型：
--
作者：
Guo, Yunlong;Gao, Yijing;Li, Qingbiao
合成、表征了纳米钯催化剂，并将其用于催化氧化挥发性有机化合物(VOC)污染物。以南瓜叶提取物为还原剂，采用生物合成方法合成了大小可调的钯纳米颗粒。然后将Pd纳米颗粒固定在以KIT-6为模板的三维有序介孔CeO2(即KIT-CeO2)制成的载体上，形成不同Pd负载量(x表示Pd负载量，wt%)的XPd/KIT-CeO2催化剂。对XPd/KIT-CeO2催化剂及其载体的形态、结构、元素分布等物化性能进行了全面的表征。载体和催化剂的BET比表面积在105-109m(2)/g范围内变化，在0.5Pd/KIT-CeO2催化苯氧化反应中，与文献报道的结果相比，苯转化率90%所需的温度显著降低到187℃。此外，0.5Pd/KIT-CeO2在在线反应中使用150h后表现出稳定的催化活性。此外，密度泛函理论计算表明，Pd纳米颗粒与Kit-CeO2载体的协同作用有利于Pd纳米颗粒氧化前吸附的苯的活化。0.5Pd/KIT-CeO2催化剂的催化性能与Cp叶提取物、Pd-0浓度高、氧物种丰富、低温可还原、Pd纳米粒子与KIT-CeO2载体相互作用强等特点密切相关。生物法合成Pd纳米粒子的催化活性优于化学法，而KIT-CeO2作为载体材料优于商品化CeO2和KIT-6模板过渡金属氧化物(如Fe2O和Co3O4)。
Pd nanoparticles (NPs)-based catalysts were synthesized, characterized and used to catalyze the oxidation of volatile organic compound (VOC) pollutants. A biogenic method was employed to synthesize Pd NPs with tunable sizes by using Cacumen platycladi (CP) leaf extract as a reducing agent. The Pd NPs were then anchored over a support which was made from KIT-6-templated three-dimensionally ordered mesoporous (3DOM) CeO2 (i.e., kit-CeO2) to form xPd/kit-CeO2 catalysts with various Pd loadings (x denotes Pd loading, wt%). The physicochemical properties such as morphology, structure and elemental distribution of the xPd/kit-CeO2 catalysts and the support were comprehensively characterized. The BET surface areas of the support and catalysts varied in the range of 105-109 m(2)/g. In the benzene oxidation catalyzed by 0.5Pd/kit-CeO2, the temperature required for 90% benzene conversion was significantly reduced to 187 degrees C, compared with the published results. Furthermore, the 0.5Pd/kit-CeO2 showed stable catalytic activity after being used for 150 h in on-stream reaction. Besides, density functional theory calculation indicated that the synergetic effects of Pd NPs and the kit-CeO2 support would facilitate the activation of benzene adsorbed on Pd NPs prior to oxidation. The catalytic performance of 0.5Pd/kit-CeO2 correlated well with the features of CP leaf extract, high Pd-0 concentration, abundant oxygen adspecies, low temperature reducibility, and strong interactions between Pd NPs and kit-CeO2 support. The biogenic method is better than the chemical method to synthesize Pd NPs with higher catalytic activity while the kit-CeO2 is better than the commercial CeO2 and KIT-6-templated transition metal oxides (e.g., Fe2O3 and Co3O4) as a supporting material.