MoO_x促进的Pt基催化剂用于低温水汽变换反应(英文)

MoO_x-promoted Pt catalysts for the water gas shift reaction at low temperatures

通过浸渍还原法制备了不同比例的Pt-Mo/SiO_2催化剂,采用X射线衍射、透射电镜、X射线近边吸收谱和X射线光电子能谱表征了Pt-Mo/SiO_2催化剂的组成、结构及价态.研究结果表明,少量MoO_x修饰Pt-Mo/SiO_2催化剂在低温水汽变换反应中表现出比Pt/SiO_2催化剂更高的催化活性,过量MoO_x包覆的Pt-Mo/SiO_2催化剂活性较低.低温水汽变换反应活性来自于Pt与表面MoO_x的界面协同作用,限域在Pt纳米颗粒表面的MoO_x表现出较低价态,高分散MoO_x纳米岛修饰的Pt纳米颗粒是低温水汽变换反应的活性结构.

Pt-Mo/SiO2 catalysts were prepared using impregnation-reduction methods. Mo-promoted Pt catalysts exhibit much higher water gas shift reaction activity at low temperatures than Pt/SiO2 catalysts. Various characterization methods including inductive coupled plasma atomic emission spectrometry, X-ray diffraction, transmission electron microscopy, X-ray absorption near edge spectrum, and X-ray photoelectron spectroscopy were applied to investigate the composition, structure and chemical state of the Pt-Mo/SiO2 catalysts. Our results indicate that the added Mo species effec- tively improves the dispersion of Pt nanoparticles and the synergistic effect between the Pt nanoparticles and surface MoOxspecies enhances the catalytic performance for the water gas shift reaction. Pt nanoparticles decorated with highly dispersed MoOx patches are found to be the active architecture.