title: Development of Pd-Cu/hematite catalyst for selective nitrate reduction.
abstract: A new hematite-supported Pd-Cu bimetallic catalyst (Pd-Cu/hematite) was developed in order to actively and selectively reduce nitrate (NO3(-)) to nitrogen gas (N2). Four different iron-bearing soil minerals (hematite (H), goethite (G), maghemite (M), and lepidocrocite (L)) were transformed to hematite by calcination and used for synthesis of different Pd-Cu/hematite-H, G, M, and L catalysts. Their characteristics were identified using X-ray diffraction (XRD), specific surface area (BET), temperature programed reduction (TPR), transmission electron microscopy with energy dispersive X-ray (TEM-EDX), H2 pulse chemisorption, zeta-potential, and X-ray photoelectron spectroscopy (XPS). Pd-Cu/hematite-H exhibited the highest NO3(-) removal (96.4%) after 90 min, while a lower removal (90.9, 51.1, and 30.5%) was observed in Pd-Cu/hematite-G, M, and L, respectively. The results of TEM-EDX, and TPR analysis revealed that Pd-Cu/hematite-H possessed the closest contact distance between the Cu and Pd sites on the hematite surface among the different Pd-Cu/hematite catalysts. The high removal can be also attributed to the highly active metallic sites on its positively charged surface. The XPS analysis demonstrated that the amount of hydrogen molecules can have a pivotal function on NO3(-) removal and a ratio of nitrogen to hydrogen molecule (N:H) on the Pd sites can critically determine N2 selectivity.
authors: Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology , 291 Daehak-ro, Yuseong-Gu, Daejeon 305-701, Korea.
authors: Sungyoon
authors: S
authors: Jung
authors: Sungjun
authors: S
authors: Bae
authors: Woojin
authors: W
authors: Lee
mesh_terms: D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry; D007501:Iron / Q000737:chemistry; D058085:Iron Compounds; D046529:Microscopy, Electron, Transmission; D008903:Minerals; D009566:Nitrates / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry; D009589:Nitrogen Oxides; D010165:Palladium / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D014961:X-Ray Diffraction
chemical_list: D005290:Ferric Compounds; D058085:Iron Compounds; D008903:Minerals; D009566:Nitrates; D009589:Nitrogen Oxides; C094886:goethite; C000499:ferric oxide; D010165:Palladium; D003300:Copper; D006859:Hydrogen; D007501:Iron; D009584:Nitrogen