关键词: 指状孔, 龟裂纹, 竞争吸附, 甲醇水蒸气重整, 反应机理

Abstract: A "top-down" design concept was adopted; herein, a porous carbon sphere-supported catalyst (Cu-Zn/CS) was fabricated by means of a wet spinning technique and a competitive impregnation adsorption method and applied for the hydrogen (H2) production via methanol steam reforming (MSR) reaction. Taking commercial Al2O3 as the comparative support, the morphological characteristics, crystal phase structure, physicochemical properties, catalytic performance, and reaction mechanism of Cu-Zn/Al2O3 and Cu-Zn/CS were compared and analyzed through a series of complementary characterizations and tests. The characterization results showed that the constructed Cu-Zn/CS had abundant multi-morphological and multi-scale pores and craquelure structures, which not only provided the necessary spatial foundation for the multiscale anchoring of active substances but also increased the contact probability between active sites and reactants during the reactions. Catalytic performance showed that, compared with the Cu-Zn/Al2O3, the CO selectivity of Cu-Zn/CS was reduced by one order of magnitude, the H2 selectivity was nearly doubled, and the high-temperature catalytic activity was better under the premise of complete methanol conversion. In addition, in-situ DRIFTS experiments indicated that at high reaction temperatures, gaseous reactants on the surface of Cu-Zn/Al2O3 not only involved the main reaction of methanol catalytic conversion to CO2 and H2 but also concerned the side reaction of generating CO. On the surface of Cu-Zn/CS, the main reaction occurs, that is, the reaction path of CH3OH + H2O → *OCH3 + *OH → *HCHO → *CHOO → *CO2 + *H2.

Key words: Finger-shaped pores, Craquelures; Competitive adsorption, Methanol steam reforming, Reaction mechanism