The various metal-doped Silicalite-1 (MÀ S1, M=Mg, Al, Fe and In) supports were prepared by hydrothermal synthesis method, then were used to disperse the PtSn species through impregnation. The resulting solids were further characterized through XRD, N 2 adsorption/desorption isotherms, XPS, H 2 -TPR, NH 3 -TPD, Raman spectroscopy and TG techniques to investigate the structural property before and after propane dehydrogenation reaction. The results exhibited that the introduction of various metal dopants had profound effects on pore structure, reducibility, acidity and surface content of Pt which was directly related to the activation of propane. And the surface content of Pt acted as the dominant role for converting propane. As a consequence, the maximum initial conversion of propane was obtained over Fe-modified PtSn/FeÀ S1 sample, but it deactivated fast as well because of the coke deposition.

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Bimetallic catalysts NiCo/CNTs with distribution-controlled Ni and Co species were prepared by modified impregnation method with the assistance of dimethylbenzene and characterized by XRD, N 2 adsorption/desorption, HAADF, TEM, XPS, TPR, and TG. The metal species could be well dispersed in calcined catalyst, and the distribution had profound influences on reducibility, surface property, and particle size. Sintering of active sites and coke deposition were mainly responsible for catalytic deactivation, and the former one played a negative role in promoting a water gas shift reaction. The sample where both Ni and Co were located in CNT caves performed the best in catalytic activity as well as in stability thanks to the confinement effect.

The Zr-, Ce-, Sr-, and Sn-promoted Cr/SiO2 catalysts were prepared by the incipient wetness impregnation method, then characterized by N2 adsorption/desorption, X-ray diffraction, X-ray photoelectron spectroscopy, H2-TPR, CO2-TPD, UV–vis, high-angle annular dark-field imaging–scanning transmission electron microscopy—energy dispersive X-ray spectroscopy elemental mapping, Raman, and thermogravimetric techniques to study the structural evolution under the preparation/reaction conditions, and applied to catalyze ethane oxidative dehydrogenation with CO2. The results suggested that the Cr6+ species were indispensable for activating the dehydrogenation reaction thanks to the oxidation–reduction cycle between Cr6+ and Cr3+. The type of the promotor also affected significantly the ability of replenishing the lattice oxygen through the disassociation of CO2, leading to the different catalytic performances. The Zr-promoted sample had the best performance in converting the reactants as well as the catalytic stability.

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