Tricobalt tetraoxide-supported palladium catalyst derived from metal organic frameworks for complete benzene oxidation

Abstract

The structure and the chemical state of the metal oxide support have significant effect on the activity of noble metal nanoparticles for the catalytic oxidation of organic pollutants. In this work, we report the synthesis of porous tricobalt tetraoxide-supported palladium (Pd/ Co 3 O 4 ) catalysts derived from direct pyrolysis of metalorganic framework (MOF) for the complete oxidation of benzene. The porosity and nanoparticle size of the catalyst could be controlled by adjusting the calcination temperature. The X-ray photoelectron spectroscopy (XPS) analyses reveal that the surface adsorbed oxygen, which is associated with the PdO x species, is crucial for catalytic performance. H 2 -temperature programmed reduction (H 2 -TPR) results indicate that the reducibility of the catalyst has significant effect on the catalytic activity for the oxidation of benzene. In general, Pd nanoparticles supported on the porous polyhedron Co 3 O 4 support calcined at 350°C (Co 3 O 4 -PP-350), which possess abundant porous structures and the most active surface adsorbed oxygen, exhibit the highest activity for the complete catalytic conversion of benzene compared with those supported on the porous polyhedron Co 3 O 4 support calcined at 250°C (Co 3 O 4 -PP-250), 550°C (Co 3 O 4 -PP-550), and the Co 3 O 4 nanoparticle support calcined at 350°C (Co 3 O 4 -NP-350). Graphical Abstract 0 50 100 150 200 250 0 20 40 60 80 100 Temperature (°C) Benzene conversion (%) 2 m Pd/Co3O4-PP-350 Pd/Co3O4-PP-550 Pd/Co3O4-PP-250 Benzene CO 2 + H 2 O 2 m 2 m

Hierarchical Pd@PC-COFs as Efficient Catalysts for Phenol Hydrogenation

“…The Pd 3d 5/2 peak at 335.35 eV and the Pd 3d 3/2 peak at 340.65 eV can be attributed to Pd(0), while the Pd 3d 5/2 peak at 337.27 eV and the Pd 3d 3/2 peak at 342.46 eV can be related to Pd(2+). 65 Only Pd(2+) is observed in fresh Pd@PC-COF-24, while both Pd(2+) and Pd(0) are detected in fresh Pd@ PC-COF-36 and Pd@PC-COF-48 (Figure 6g−i). The high Pd(0) proportion in Pd@PC-COF-36 may be caused by the high specific surface area and large mesoporous ratio of PC-COF-36 (Figure 3 and Table 1).…”

“…The peak splitting results of C and N are consistent with the composition of PC-COFs synthesized by the polymerization of cyanuric chloride and piperazine, which further confirms the successful synthesis of PC-COFs. The Pd 3d 5/2 peak at 335.35 eV and the Pd 3d 3/2 peak at 340.65 eV can be attributed to Pd(0), while the Pd 3d 5/2 peak at 337.27 eV and the Pd 3d 3/2 peak at 342.46 eV can be related to Pd­(2+) . Only Pd­(2+) is observed in fresh Pd@PC-COF-24, while both Pd­(2+) and Pd(0) are detected in fresh Pd@PC-COF-36 and Pd@PC-COF-48 (Figure g–i).…”

Recent Advances in the Catalytic Oxidation of Volatile Organic Compounds: A Review Based on Pollutant Sorts and Sources

“…168,[353][354][355] The addition of Pd to a Co/Al2O3 catalyst was determined to increase the quantity of active oxygen species on the surface of the catalyst and enhance the dispersion of Co3O4 on the surface of Al2O3. 356 A novel route for the preparation of porous catalysts was explored by Li et al 357 for application in total oxidation reactions. For this, a porous Co3O4-supported Pd catalysts was synthesized by the pyrolysis of a metal organic framework (MOF).…”

“…It is widely acknowledged that supported Pd catalysts are the most efficient catalysts for aromatic hydrocarbon oxidation. ,, Numerous reports have investigated the use of Al 2 O 3 , molecular sieves, and pillared clays as supports for Pd nanoparticles in benzene destruction. ,− The addition of Pd to a Co/Al 2 O 3 catalyst was determined to increase the quantity of active oxygen species on catalyst surface and enhance the dispersion of Co 3 O 4 on the surface of Al 2 O 3 . A novel route for the synthesis of porous catalysts was explored by Li et al for application in total oxidation reactions. For this, a porous Co 3 O 4 -supported Pd catalyst was synthesized by the pyrolysis of a metal–organic framework (MOF).…”

Metal organic frameworks as precursors for the manufacture of advanced catalytic materials

“…76 For complete oxidation of benzene to CO 2 and H 2 O in this case, Li et al studied tricobalt tetraoxidesupported palladium catalysts derived from MOFs. 77 Porous polyhedron (PP) Co 3 O 4 catalysts were prepared through onestep calcination of ZIF-67 in a muffle oven at an elevated temperature (250, 350, or 550 1C) at a ramping rate of 1 1C min À1 and held for 1 h. Finally, Pd/Co 3 O 4 -PP-X (X = 250, 350, or 550 1C) were prepared by a conventional impregnation method and subjected to calcination at 200 1C for 4 h. Among the MOF derived catalysts obtained at different temperatures, Co 3 O 4 -PP-350 exhibited the highest activity for the complete catalytic conversion of benzene. This catalyst also showed better performance than that of Pd supported on Co 3 O 4 nanoparticles (NPs) prepared by a hydrothermal method and calcined at the same temperature.…”