title: Catalytic decomposition of toxic chemicals over metal-promoted carbon nanotubes.
abstract: Effective decomposition of toxic gaseous compounds is important for pollution control at many chemical manufacturing plants. This study explores catalytic decomposition of phosphine (PH(3)) using novel metal-promoted carbon nanotubes (CNTs). The cerium-promoted Co/CNTs catalysts (CoCe/CNTs) are synthesized by means of coimpregnation method and reduced by three different methods (H(2), KBH(4), NaH(2)PO(2)·H(2)O/KBH(4)). The morphology, structure, and composition of the catalysts are characterized using a number of analytical instrumentations including high-resolution transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, BET surface area measurement, and inductively coupled plasma. The activity of the catalysts in PH(3) decomposition reaction is measured and correlated with their surface and structural properties. The characterization results show that the CoCe/CNTs catalyst reduced by H(2) possesses small particles and is shown thermally stable in PH(3) decomposition reaction. The activities of these catalysts are compared and are shown in the following sequence: CoCe/CNTs > Co/CNTs > CoCeBP/CNTs> CoCeB/CNTs. The difference in reduction method results in the formation of different active phases during the PH(3) decomposition reaction. After a catalytic activity test, only the CoP phase is formed on CoCe/CNTs and Co/CNTs catalysts, whereas multiphases CoP, Co(2)P, and Co phases are formed on CoCeBP/CNTs and CoCeB/CNTs. Results show that the CoP phase is formed predominantly on the CoCe/CNTs and Co/CNTs catalysts and is found to likely be the most active phase for this reaction. Furthermore, the CoCe/CNTs catalyst exhibits not only highest activity but also long-term stability in PH(3) decomposition reaction. When operated in a fixed-bed reactor at 360 °C, single-pass PH(3) conversion of about 99.8% can be achieved.
authors.affiliation: College of Environmental Science and Engineering, Nankai University, Tianjin, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Li
authors.forename: Changxiu
authors.initials: C
authors.lastname: Han
authors.forename: Xinyu
authors.initials: X
authors.lastname: Han
authors.forename: Yixiao
authors.initials: Y
authors.lastname: Zhou
authors.forename: Li
authors.initials: L
authors.lastname: Yang
authors.forename: Baogui
authors.initials: B
authors.lastname: Zhang
authors.forename: Jianli
authors.initials: J
authors.lastname: Hu
mesh_terms: D000393:Air Pollutants / Q000737:chemistry*; D002384:Catalysis; D002563:Cerium / Q000737:chemistry*; D006256:Hazardous Waste / Q000032:analysis*; D046529:Microscopy, Electron, Transmission; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D010720:Phosphines / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D000393:Air Pollutants; D006256:Hazardous Waste; D037742:Nanotubes, Carbon; D010720:Phosphines; D002563:Cerium; C044646:phosphine