Time differential perturbed angular correlation of. gamma. -rays emitted from sup 99 Mo yields sup 99 Tc in molybdenum-based catalysts: The nature of molybdate species in molybdena/alumina catalysts

Journal Article · Tue Feb 28 23:00:00 EST 1989 · Journal of Catalysis; (USA)

DOI:https://doi.org/10.1016/0021-9517(89)90073-0· OSTI ID:6380757

Butz, T ^[1]; Vogdt, C ^[2]; Lerf, A ^[3]; Knoezinger, H ^[4]

---

1. Technische Universitaet Muenchen (West Germany)
2. Universitaet Muenchen (West Germany) Walther-Meissner-Institut fuer Tieftemperaturforschung (West Germany)
3. Walther-Meissner-Institut fuer Tieftemperaturforschung (West Germany)
4. Universitaet Muenchen (West Germany)

The time differential observation of the perturbed angular correlation of {gamma}-rays emitted from radioactive {sup 99}Mo {yields} {sup 99}Tc allows one to characterize different Mo species by their nuclear quadrupole interaction. An elementary introduction to this hyperfine spectroscopy is given together with examples of its application to crystalline MO compounds, molybdate solutions at 77 and 300 K, and molybdates adsorbed on Al{sub 2}O{sub 3} in the impregnated as well as in the dried and calcined state. It is shown that at sufficiently high solutions concentrations, the heptamolybdate anion is adsorbed on the Al{sub 2}O{sub 3} surface. Decondensation prior to adsorption can be excluded. The adsorbed heptamolybdate species are stable during the drying and calcination process. Postimpregnation of calcined Mo/Al{sub 2}O{sub 3} catalysts with K{sub 2}CO{sub 3} leads to decondensation, the extent of which depends on K{sub 2}CO{sub 3} loading.

• OSTI ID: 6380757
• Journal Information: Journal of Catalysis; (USA), Journal Name: Journal of Catalysis; (USA) Vol. 116:1; ISSN 0021-9517; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ADSORPTION
ALKALI METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBON COMPOUNDS
CARBONATES
CATALYST SUPPORTS
CATALYSTS
CHALCOGENIDES
CHEMICAL REACTIONS
CRYSTAL STRUCTURE
DAYS LIVING RADIOISOTOPES
DENITRIFICATION
DESULFURIZATION
ELECTROMAGNETIC RADIATION
ELEMENTS
EVEN-ODD NUCLEI
FISCHER-TROPSCH SYNTHESIS
GAMMA RADIATION
GAMMA SPECTROSCOPY
HOURS LIVING RADIOISOTOPES
IMPREGNATION
INTERMEDIATE MASS NUCLEI
IONIZING RADIATIONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
METALS
METHANATION
MICROSTRUCTURE
MOLYBDATES
MOLYBDENUM
MOLYBDENUM 99
MOLYBDENUM COMPOUNDS
MOLYBDENUM ISOTOPES
MOLYBDENUM OXIDES
NUCLEI
ODD-EVEN NUCLEI
OXIDES
OXYGEN COMPOUNDS
POTASSIUM CARBONATES
POTASSIUM COMPOUNDS
RADIATIONS
RADIOISOTOPES
REFRACTORY METAL COMPOUNDS
SORPTION
SPECTROSCOPY
SURFACE PROPERTIES
TECHNETIUM 99
TECHNETIUM ISOTOPES
TIME DEPENDENCE
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
WATER GAS PROCESSES
YEARS LIVING RADIOISOTOPES