Nanophase-separated Ni3Nb as an automobile exhaust catalyst. Issue 5 (23rd March 2017)

• Record Type: Journal Article
• Authors: Tanabe, Toyokazu; Imai, Tsubasa; Tokunaga, Tomoharu; Arai, Shigeo; Yamamoto, Yuta; Ueda, Shigenori; Ramesh, Gubbala V.; Nagao, Satoshi; Hirata, Hirohito; Matsumoto, Shin-ichi; Fujita, Takeshi; Abe, Hideki
• Is Part Of: Chemical science. Volume 8:Issue 5(2017)
• Page Start: 3374
• Page End: 3378
• Publication Date: 2017-03-23
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c6sc05473k
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : Nanophase-separated Ni3 Nb alloy exhibited higher performance than traditional Pt catalysts toward the remediation of automobile exhaust. Abstract : Catalytic remediation of automobile exhaust has relied on precious metals (PMs) including platinum (Pt). Herein, we report that an intermetallic phase of Ni and niobium (Nb) ( i.e., Ni3 Nb) exhibits a significantly higher activity than that of Pt for the remediation of the most toxic gas in exhaust ( i.e., nitrogen monoxide (NO)) in the presence of carbon monoxide (CO). When subjected to the exhaust-remediation atmosphere, Ni3 Nb spontaneously evolves into a catalytically active nanophase-separated structure consisting of filamentous Ni networks (thickness < 10 nm) that are incorporated in a niobium oxide matrix ( i.e., NbO x ( x < 5/2)). The exposure of the filamentous Ni promotes NO dissociation, CO oxidation and N2 generation, and the NbO x matrix absorbs excessive nitrogen adatoms to retain the active Ni 0 sites at the metal/oxide interface. Furthermore, the NbO x matrix immobilizes the filamentous Ni at elevated temperatures to produce long-term and stable catalytic performance over hundreds of hours.