Selective catalytic reduction of NO with methane on gallium catalysts

Journal Article · Sat Jan 01 04:00:00 EST 1994 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1006/jcat.1994.1001· OSTI ID:7288319

Li, Yuejin; Armor, J N ^[1]

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1. Air Products and Chemicals, Inc., Allentown (United States)

Gallium species supported on H-ZSM-5 and on H-mordenite are active catalysts for NO reduction with methane in the presence of excess O[sub 2]. Over Ga-H-ZSM-5, the NO reduction rate is first order in NO with a variable, fractional order in CH[sub 4]. The distinct feature of these gallium-based catalysts is their very high CH[sub 4] selectivities for NO[sub x] reduction. Ga-H-Y, on the other hand, is a poor catalyst for this reaction. The preparation method, ion exchange or wet impregnation, does not appear to be critical for the performance of a Ga/H-ZSM-5 catalyst. Gallium-exchanged and impregnated H-ZSM-5 have similar activities for the NO reduction. Comparable Broensted acid sites were found on the H-ZSM-5 and the H-ZSM-5 supported gallium catalysts via temperature-programmed desorption measurements with ammonia and isopropylamine and by infrared measurements. On the other hand, the presence of H[sup +] in zeolite is important; Ga/Na-ZSM-5 was inactive for the NO reduction. It is apparent that a synergism exists between gallium species and H[sup +], and this serves to activate CH[sub 4] as a reductant for NO in the presence of O[sub 2]. While Ga-H-ZSM-5 is more selective than Co-ZSM-5 for NO reduction, it is more sensitive to water, which makes it less attractive for commercial applications. 35 refs., 6 figs., 3 tabs.

• OSTI ID: 7288319
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 145:1; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ABSORPTION SPECTROSCOPY
CATALYSIS
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
ELEMENTS
GALLIUM
HETEROGENEOUS CATALYSIS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
KINETICS
MATERIALS
METALS
MINERALS
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN OXIDES
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
REDUCTION
SILICATE MINERALS
SPECTROSCOPY
ZEOLITES