Synthesis of Fe-ZrO2 nanocomposite powders by reduction in H2 of a nanocrystalline (Zr, Fe)O2 solid solution

Abstract

a b s t r a c tThe formation of Fe-ZrO 2 nanocomposite powders by reduction in hydrogen of a nanocrystalline totally stabilized Zr 0.9 Fe 0.1 O 1.95 solid solution was investigated by X-ray diffraction (XRD), field-emission-gun scanning electron microscopy (FEG-SEM) and Mössbauer spectroscopy. The reduction of the stabilized Zr 0.9 Fe 0.1 O 1.95 solid solution and the formation of metallic particles precedes the transformation of zirconia into the monoclinic phase, which becomes the major zirconia phase upon reduction at 950 • C. ␣-Fe particles with a size distribution slightly increasing from 10-50 to 20-70 nm upon the increase in reduction temperature are observed and a second population of smaller (<5 nm) ␥-Fe nanoparticles is also noticed when the reduction is performed at 1000 • C. Another metallic phase with a hyperfine field of ∼200 kOe at RT (∼250 kOe at 80 K) is detected, which could account for an Fe/Zr phase. It could be formed by the reduction on an Fe 2+ -rich transient phase incorporating a small fraction of the Zr 4+ ions, formed by a phase partitioning process superimposed to the reduciton processes.

Synthesis of ZrO2:Fe nanostructures with visible-light driven H2 evolution activity

“…Developing junction material systems with synergic benets from individuals is of great signicance. [12][13][14][15] However, due to the hybridization of the atomic orbital, almost all of the metal dopants in ZrO 2 would reduce the energy level of CBM. [5][6][7] Furthermore, the hybrid system needs many photocatalysis materials, which have the conduction band minimum (CBM) and valence band maximum (VBM) in a variety of energy levels to create bandstructure matched hybrid composites.…”

Iron-stabilized nanocrystalline ZrO2 solid solutions: Synthesis by combustion and thermal stability

“…An exhaustive Mö ssbauer spectroscopy study was performed. The formation of Fe-ZrO 2 nanocomposite powders by selective reduction of the solid solution in hydrogen will be reported elsewhere [30].…”

Intragranular Tungsten/Zirconium Carbide Nanocomposites via a Selective Liquid/Solid Displacement Reaction

“…Composite materials consisting of transition metal nanoparticles within a ceramic matrix or shell can exhibit a variety of attractive magnetic, electrical, electrochemical, optical, thermal, chemical, biomedical, and mechanical properties . The syntheses of transition metal nanoparticles dispersed within oxide matrices has been accomplished via the selective internal reduction of homogeneous oxide solid solutions with gaseous reducing agents (e.g., H 2 , CO) . However, the conversion of non‐oxide solid solutions into metal nanoparticles dispersed within non‐oxide matrices has not been reported.…”

“…[1][2][3][4][5][6][7][8] The syntheses of transition metal nanoparticles dispersed within oxide matrices has been accomplished via the selective internal reduction of homogeneous oxide solid solutions with gaseous reducing agents (e.g., H 2 , CO). [9][10][11] However, the conversion of non-oxide solid solutions into metal nanoparticles dispersed within non-oxide matrices has not been reported. Here, we demonstrate, for the first time, the conversion of carbide solid solutions into carbide matrices with embedded metal nanoparticles.…”