Guilin Zhou

Pd/CeO ₂ catalysts with different metallic Pd loading were synthesized by impregnation method. The physicochemical properties of prepared Pd/CeO ₂ catalysts and corresponding precursors were studied by XRD, XPS, H ₂ -TPD and H ₂ -TPR. Moreover, the catalytic performance of the Pd/CeO ₂ catalysts was investigated via gas phase benzene hydrogenation reaction at the temperature of 100–200 °C under atmosphere pressure. Results show that the catalytic performance of prepared Pd/CeO ₂ catalysts is directly related to the metallic Pd content. The amounts of active metallic Pd and adsorbed-desorbed hydrogen species on Pd/CeO ₂ catalysts increase with the increasing metallic Pd loading from 1.0 to 3.0%, while the numbers of them are slightly reduced on Pd/CeO ₂ (3.5) catalyst. Furthermore, metallic Pd is highly dispersed on the nano-CeO ₂ supports, therefore, the prepared Pd/CeO ₂ catalysts present good gas phase benzene catalytic hydrogenation performance. At 200 °C, the benzene conversion over the Pd/CeO ₂ catalysts with different metallic Pd loading follows the rule: Pd/CeO ₂ (3.0) > Pd/CeO ₂ (3.5) > Pd/CeO ₂ (2.5) > Pd/CeO ₂ (2.0) > Pd/CeO ₂ (1.5) > Pd/CeO ₂ (1.0), corresponding values are 94.3, 96.4, 89.9, 82.8, 72.7, 42.6 and 94.3%. And the cyclohexane selectivity is 100% on all prepared Pd/CeO ₂ catalysts.

The mesoporous Ni/KIT-6 catalysts with different composition were prepared by altering reduction temperatures. In addition, their physicochemical properties were characterized by X-ray diffraction, in-situ X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller techniques. The results shown that the specific surface area, composition and metallic Ni crystallinity of the Ni/KIT-6 catalyst were significantly affected by reduction temperatures. The catalytic performances of the prepared Ni/KIT-6 catalysts were evaluated via the CO₂ reforming of CH₄ into syngas and followed the order: RT0 < RT250 < RT300 < RT350 < RT400 < RT450 ≈ RT500. The specific surface area, pore volume, pore diameter, and Ni⁰ content of the most representative RT450 catalyst among of them were 646.7 m² g⁻¹, 0.92 cm³ g⁻¹, 6.5 nm, and 30.9%, respectively. The CH₄ and CO₂ conversions of RT450 catalyst reached to 69.0 and 39.4% under a reaction temperature of 600 °C, respectively. The CO selectivity was greater than 49% and the RT450 catalyst had good stability.

CuO/KIT-6 catalyst was prepared by the excess impregnation method, and used for ethanol selective catalytic oxidation to produce acetaldehyde. The properties of the prepared CuO/KIT-6 catalyst were investigated by XRD and TEM. The results indicate that the synthesized CuO/KIT-6 catalyst still retains highly ordered mesoporous structure with well-dispersed CuO species. The CuO/KIT-6 catalyst shows predominant ethanol selective catalytic oxidation activities. The ethanol conversion and acetaldehyde selectivity of the CuO/KIT-6 catalyst at 275°C are 93.8% and 96.6%, respectively. The CuO/KIT-6 catalyst has high ethanol selective catalytic oxidation activity and acetaldehyde selectivity, which can be attributed to the highly ordered mesoporous structure and well-dispersed CuO species.

The present work investigates the catalytic properties of the Co-Ni-supported activated carbon (AC) catalyst for the oxidation removal of CO in excess hydrogen gas to obtain High purity hydrogen. X-ray diffraction (XRD), temperatureprogrammed desorption of O2 (O2-TPD), and temperature-programmed reduction (TPR) were used to study the properties of the prepared catalyst. XRD, and TPR results indicate that the highly dispersed NiO and Co3O4 are the main phase in the prepared catalyst. The O2-TPD results show that the Co3O4-NiO/AC catalyst has strong adsorption and activation capacity to O2 molecules. Active oxygen species can be formed on the surface of Co3O4-NiO/AC catalyst, which is the active species to oxidize CO molecules. CO conversion can exceed 99.5% in the temperature range of 443∼463 K, and CO oxidation selectivity exceeds 62.2% in less than 463 K.