Nickel-silica nanocomposites were prepared by the sol-gel route. By subjecting these to an oxidation treatment in the temperature range 723-1023 K, nickel oxide films of estimated thicknesses in the range 0.5-1.5 nm were grown on the nickel nanoparticles. dc electrical resistivity was measured in the temperature range 300-570 K. The data indicate that an amorphous phase in the interfacial region of the oxide-coated nickel nanoparticles determines the electrical conduction. A small polaron hopping conduction is found to be operative. The humidity sensing properties of these nanocomposites were measured at 300 K in the range of relative humidity (RH) from 3% to 87%. Electrical conductance in all specimens showed an increase of about three orders of magnitude as the RH was raised. Specimens subjected to higher oxidation treatment showed a higher conductance for a specific value of RH. This is ascribed to the presence of a larger number of Ni3+ ions in such specimens. © 2000 American Institute of Physics.
D., D., M., P., DI BARTOLOMEO, E., Traversa, E., D., C. (2000). Synthesis of nanocrystalline nickel oxide by controlled oxidation of nickel nanoparticles and their humidity sensing properties. JOURNAL OF APPLIED PHYSICS, 88(11), 6856-6860.
Synthesis of nanocrystalline nickel oxide by controlled oxidation of nickel nanoparticles and their humidity sensing properties
DI BARTOLOMEO, ELISABETTA;TRAVERSA, ENRICO;
2000-01-01
Abstract
Nickel-silica nanocomposites were prepared by the sol-gel route. By subjecting these to an oxidation treatment in the temperature range 723-1023 K, nickel oxide films of estimated thicknesses in the range 0.5-1.5 nm were grown on the nickel nanoparticles. dc electrical resistivity was measured in the temperature range 300-570 K. The data indicate that an amorphous phase in the interfacial region of the oxide-coated nickel nanoparticles determines the electrical conduction. A small polaron hopping conduction is found to be operative. The humidity sensing properties of these nanocomposites were measured at 300 K in the range of relative humidity (RH) from 3% to 87%. Electrical conductance in all specimens showed an increase of about three orders of magnitude as the RH was raised. Specimens subjected to higher oxidation treatment showed a higher conductance for a specific value of RH. This is ascribed to the presence of a larger number of Ni3+ ions in such specimens. © 2000 American Institute of Physics.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
