Ceria nanorod supported gold nanoparticles as structured catalysts for the oxidative steam reforming of methanol: Effect of CTAB concentration on physiochemical properties and catalyst performance
2020
Eaimsumang, Srisin | Chollacoop, Nuwong | Luengnaruemitchai, Apanee | Taylor, Stuart H.
Ceria (CeO₂) supports were synthesized by hydrothermal treatment with different Cetyltrimethylammonium bromide (CTAB) concentrations (CeO₂-X: 0.135, 0.270, 0.540 and 1.080, where X is the CTAB concentration in mmol). The micro-structures of bundle-like ceria nanorods (NR) were produced by thermal treatment of the crystalline Ce(OH)CO₃ precursor. The exposed crystal planes of (200) and (111), corresponding to the d-spacing of 0.27 and 0.31 nm, were confirmed by high resolution-transmission electron microscopy (HR-TEM). The fundamental characteristics of CeO₂-0.135 led to the highest surface area, surface area normalized reducibility and oxidized gold species (Auⁿ⁺/Au⁰) on the surface, relatively higher oxygen vacancies and a smaller average gold particle size (7.9 nm). The activity results show that the Au/CeO₂-0.135 has the highest methanol conversion and H₂ production rate for oxidative steam reforming of methanol (OSRM). The reducibility and gold particle size played a crucial role in determining the H₂/CO₂ ratio at the temperature of 200 °C.
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