Nanocrystalline ferrites Ni{sub x}Zn{sub 1-x}Fe{sub 2}O{sub 4}: Influence of cation distribution on acidic and gas sensing properties

Journal Article · Sat Oct 15 00:00:00 EDT 2011 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2011.08.029· OSTI ID:21580041

Kazin, A P ^[1]; Prusakov, V E; Suzdalev, I P ^[2]; Gaskov, A M ^[1]

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1. Chemistry Department, Moscow State University, Leninskie Gory 1-3, 119991 Moscow (Russian Federation)
2. Institute of Chemical Physics, 119991 Moscow (Russian Federation)

This work is devoted to a detailed analysis of the interconnection between composition, cation distribution and acidic properties of the surface of nanocrystalline ferrites Ni{sub x}Zn{sub 1-x}Fe{sub 2}O{sub 4} obtained by aerosol pyrolysis. The detailed analysis of the Moessbauer spectra allows us to determine the distribution of cations between tetrahedral and octahedral positions in spinel structure. Depending on samples composition, the tetrahedral positions can be occupied by only Fe{sup 3+} cations (inverse spinel, x{>=}0.4) or by Fe{sup 3+} and Zn{sup 2+} cations (mixed spinel, x=0, 0.2). Increasing the nickel concentration in the ferrite leads to decrease in the number of strong acid centers on the surface. It was found that the decrease in the contribution of strong surface acid sites leads to an increase in sensory sensitivity of the ferrite towards ammonia. For ethanol detection an inverse relationship between sensor signal and surface acidity was observed. - Graphical abstract: (a) n- and p-types change in electrical resistance and (b) sensor signal of Ni{sub x}Zn{sub 1-x}Fe{sub 2}O{sub 4} towards NH{sub 3} and ethanol vapor vs. the part of strong acid sites. Highlights: > Relationship between composition, cation distribution, and acidity in nanocrystalline Ni{sub x}Zn{sub 1-x}Fe{sub 2}O{sub 4}. > Degree of inversion of spinel is determined by Moessbauer spectroscopy. > Increase of nickel content leads to decrease in the number of strong acid centers. > This results in an increase in sensory sensitivity of the ferrite towards ammonia. > Relationship between sensor signal to ethanol and surface acidity is opposite.

• OSTI ID: 21580041
• Journal Information: Journal of Solid State Chemistry, Vol. 184, Issue 10; Other Information: DOI: 10.1016/j.jssc.2011.08.029; PII: S0022-4596(11)00469-5; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
AEROSOLS
AMMONIA
CATIONS
CRYSTALS
DETECTION
DISTRIBUTION
ELECTRIC CONDUCTIVITY
ETHANOL
FERRITE
FERRITES
IRON IONS
MOESSBAUER EFFECT
NANOSTRUCTURES
NICKEL
PYROLYSIS
SENSITIVITY
SENSORS
SPINELS
SURFACES
ZINC IONS
ALCOHOLS
ALLOYS
CARBON ADDITIONS
CHARGED PARTICLES
CHEMICAL REACTIONS
COLLOIDS
DECOMPOSITION
DISPERSIONS
ELECTRICAL PROPERTIES
ELEMENTS
FERRIMAGNETIC MATERIALS
HYDRIDES
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
IONS
IRON ALLOYS
IRON COMPOUNDS
MAGNETIC MATERIALS
MATERIALS
METALS
MINERALS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
ORGANIC COMPOUNDS
OXIDE MINERALS
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SOLS
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENT ALLOYS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS