We report a simple method for preparing copper（II） molybdate（CuMoO_4） powders via a combustion-like process. A gel was first prepared by the polymerizable complex method, where citric acid was used as a complexing...We report a simple method for preparing copper（II） molybdate（CuMoO_4） powders via a combustion-like process. A gel was first prepared by the polymerizable complex method, where citric acid was used as a complexing and polymerizing agent and nitric acid was used as an oxidizing agent. The thermal decomposition behavior of the（CuMo）-precursor gel was studied by thermogravimetry–differential thermal analysis（TG–DTA）, Fourier transform infrared spectroscopy（FTIR）, and X-ray diffraction（XRD）. We observed that the crystallization of CuMoO_4 powder was completed at 450°C. The obtained homogeneous powder was composed of grains with sizes in the range from 150 to 500 nm and exhibited a specific surface area of approximately 5 m^2/g. The average grain size increased with increasing annealing temperature. The as-prepared CuMoO_4 crystals showed a strong green photoluminescence emission at room temperature under excitation at 290 nm, which we mainly interpreted on the basis of the Jahn-Teller effect on [MoO_4^（2-）] complex anions. We also observed that the photoluminescence intensity increased with increasing crystallite size.展开更多
Breakthroughs can be expected in multi-component ceramics by adjusting the phase assembly and the micro–nanostructure.Controlling the architecture of multi-materials at different scales is still challenging and provi...Breakthroughs can be expected in multi-component ceramics by adjusting the phase assembly and the micro–nanostructure.Controlling the architecture of multi-materials at different scales is still challenging and provides a great opportunity to broaden the range of functionalities in the field of ferroelectric-based ceramics.We used the potentialities of Spark Plasma Sintering(SPS)to control a number of key parameters regarding the properties:anisotropy,interfaces,grain size and strain effects.The flexibility of the wet and supercritical chemistry routes associated with the versatility of SPS allowed designing newferroelectric composite ceramics at different scales.These approaches are illustrated through various examples based on our work on ferroelectric/dielectric composites.展开更多
基金supported by two French-Moroccan projects: Volubilis Partenariat Hubert Curien (PHC No.MA 09 205)Projet de Recherches Convention Internationale du CNRS (CNRS-CNRST No.w22572)
文摘We report a simple method for preparing copper（II） molybdate（CuMoO_4） powders via a combustion-like process. A gel was first prepared by the polymerizable complex method, where citric acid was used as a complexing and polymerizing agent and nitric acid was used as an oxidizing agent. The thermal decomposition behavior of the（CuMo）-precursor gel was studied by thermogravimetry–differential thermal analysis（TG–DTA）, Fourier transform infrared spectroscopy（FTIR）, and X-ray diffraction（XRD）. We observed that the crystallization of CuMoO_4 powder was completed at 450°C. The obtained homogeneous powder was composed of grains with sizes in the range from 150 to 500 nm and exhibited a specific surface area of approximately 5 m^2/g. The average grain size increased with increasing annealing temperature. The as-prepared CuMoO_4 crystals showed a strong green photoluminescence emission at room temperature under excitation at 290 nm, which we mainly interpreted on the basis of the Jahn-Teller effect on [MoO_4^（2-）] complex anions. We also observed that the photoluminescence intensity increased with increasing crystallite size.
基金Financial support from the French National Center for Scientific Research(CNRS),the Conseil Regional d'Aquitaine,and the National Research Agency(ANR)(Projects NANO4F(ANR-05-JCJC-0169)ARCHIFUN(ANR-12-BS08–009)are gratefully acknowledged.
文摘Breakthroughs can be expected in multi-component ceramics by adjusting the phase assembly and the micro–nanostructure.Controlling the architecture of multi-materials at different scales is still challenging and provides a great opportunity to broaden the range of functionalities in the field of ferroelectric-based ceramics.We used the potentialities of Spark Plasma Sintering(SPS)to control a number of key parameters regarding the properties:anisotropy,interfaces,grain size and strain effects.The flexibility of the wet and supercritical chemistry routes associated with the versatility of SPS allowed designing newferroelectric composite ceramics at different scales.These approaches are illustrated through various examples based on our work on ferroelectric/dielectric composites.
