核-壳结构Pd-Co3O4@SiO2催化剂的低浓度甲烷催化燃烧性能

用自组装法制备了一种具有核–壳结构的Pd-Co₃O₄@SiO₂催化剂,对其低浓度甲烷催化燃烧性能进行了研究。TEM、XRD、H₂-TPR表征及催化活性测试结果表明,SiO₂壳内的PdO与CoO_x之间的强相互作用,使得Pd-Co₃O₄@SiO₂对低浓度甲烷燃烧具有优异的催化活性。同时,与负载型Pd/Co₃O₄-SiO₂及Pd/Co₃O₄@SiO₂催化剂相比,核-壳型Pd-Co₃O₄@SiO₂催化剂经800 ℃煅烧后仍能保持较好的核-壳结构,有效地避免了Pd和Co活性物种的高温烧结,因而具有更高的热稳定性。

Catalytic combustion of lean methane over a core-shell structured Pd-Co3 O4@SiO2 catalyst

A core-shell structured Pd-Co₃O₄@SiO₂ catalyst was prepared by a simple self-assemble method and used in lean methane combustion. The results of catalytic tests indicate that the core-shell Pd-Co₃O₄@SiO₂ catalyst exhibits high activity in lean methane combustion and superior stability at high temperature. The results of TEM, XRD, and H₂-TPR characterization suggest that the high activity of Pd-Co₃O₄@SiO₂ is mainly ascribed to the strong interaction between CoO_x and PdO species inside the SiO₂ shell. Meanwhile, as the active Pd and CoO_x species in Pd-Co₃O₄@SiO₂ are enshielded in the core-shell structure, which is effective to protect the active phase from sintering at high temperature, the core-shell structured Pd-Co₃O₄@SiO₂ catalyst is thus far superior in thermal stability against high temperature to the supported Pd/Co₃O₄@SiO₂ and Pd/Co₃O₄-SiO₂ catalysts.