Filter and buffer-pot confinement effect of hollow sphere catalyst for promoted activity and enhanced selectivity

Abstract

To efficiently utilize the catalyst active sites and simultaneously enhance target hydrocarbon selectivity in Fischer-Tropsch synthesis (FTS), herein, we demonstrate a promising Co-Al 2 O 3 hollow-sphere catalyst prepared by a two-pot route including hydrothermal carbonization and wet impregnation. Benefiting by plentiful mesopores on the shell, reactants could access the cavity inside and the active sites on the inner surface for further FTS reaction. Compared with conventional solid catalyst, the hollow structure provided a "buffer-pot" effect, where feed gas and preliminary product from the shell could mix completely at a low flow rate. Heavy hydrocarbons were further confined, leading to enhanced formation of lighter C 5 -C 11 components, which more readily escaped out through the mesoporous shell, which thus played a "filter" role. Additionally, increased acidity on the shell generated more isoparaffins and olefins in the final product. This concept displayed a great superiority in improving active metal activity and selective production from multiple products compared with conventional supported catalysts.

Functionalized Natural Carbon‐Supported Nanoparticles as Excellent Catalysts for Hydrocarbon Production

“…In addition, the Ramans hifts of 465, 510, and 670 cm À1 for the Co@NC and CoX catalysts are ascribed to the E g ,F 1 2g ,a nd A 1g modes of the crystalline Co 3 O 4 ,r espectively. [16,19] No clear corresponding peaks of cobalto xide in the Co@C catalyst are observed, which is in good accord with the XRD analysis.…”

Hollow Structure and Electron Promotion Effect of Mesoporous Pd/CeO2 Catalyst for Enhanced Catalytic Hydrogenation

“…SEM images of Al 2 O 3 hollow spheres supported Pd (Pd/Al 2 O 3 ‐H) and general CeO 2 supported Pd (Pd/CeO 2 ‐G) as reference catalysts are also shown in Figure e,f. Compared with CeO 2 ‐H hollow spheres, Al 2 O 3 spheres were significantly larger, and the outer shells were composed of lamellar Al 2 O 3 particles, whereas there were no apparent pores observed on the Pd/CeO 2 ‐G, which could result from the used solid‐state grinding method.…”

“…Clearly, the samples prepared by the glucose hydrothermal carbonization method exhibited type IV isotherms, which were characteristic of mesoporous materials. In terms of Al 2 O 3 ‐H and Pd/Al 2 O 3 ‐H catalysts, the hysteresis loops were classified as type H2, reflecting the well‐developed pore channel connectivity with ink‐bottle‐like pores . For the CeO 2 ‐H and Pd/CeO 2 ‐H samples, the hysteresis loops presented combined characteristics of type H3 and H4, meaning that slit‐like pores or wedge‐shaped pores were fabricated .…”

Selectively Converting Biomass to Jet Fuel in Large‐scale Apparatus

“…This is attributed to the oxidation process of metallic cobalt with a complete oxidation process at approximately 370 °C . In the case of the used catalyst, a more intense exothermic peak is present at close to 300 °C owing to the highly exothermic process of wax combustion . A continuous weight loss is observed until 290 °C, corresponding to the water evaporation and combustion process of wax product with high boiling points above 250 °C.…”