Facile synthesis of monodispersed copper oxalate flaky particles in the presence of EDTA

Monodispersed copper oxalate paxticles with flaky morphology were prepared via a simple one-pot synthesis method. Scanning electron microscope （SEM）, X-ray diffraction （XRD）, and fourier tza^sform infraJced （FTIR） spectra were used to characterize paxticle mor- phology, size, phase composition, and functional groups. It was found that the presence of ethylenediaminetetzaacetic acid （EDTA） and the solution pH value had strong influence on the morphological and size evolution of the precipitated particles. On the basis of controlled re- lease of copper ions from a Cu2＋-EDTA complex and Weimazn＇s law, a stzategy for the controlled synthesis of monodispersed copper oxa- late paxticles was designed by refemng to the basic mode of the St0ber method. The inherent nature of crystallization to form the flaky solid in the early stage of precipitation as well as the driving force of the long-lasting low supersaturation in the growth stage was proposed to ex- plain the size and morphological evolution of the copper oxalate precipitates. Thermodynamic equilibrium concentrations of copper（II） spe- cies in the Cu（II）-EDTA-oxalate-H20 solution system were calculated to help explain the possible formation mechaNsm of copper oxalate precipitates.

Synthesis of Copper Oxalate Nanorods by a Simple One-step Solid-state Chemical Reaction Method

Copper oxalate nanorods were successfully prepared by means of a simple one-step solid-state reaction method with the assistance of a suitable surfactant, polyethylene glycol 400. The product with uniform rod-like morphology was characterized by XRD, TEM and SEM. The formational mechanism of the rod-like structure was also preliminary discussed.

Preparation and Kinetics of the Thermal Decomposition of Nanosized CuC_2O_4-ZnC_2O_452H_2O

The physical mixture of nanosized CuC2O4-ZnC2O4·2H2O, as precursors of CuO-ZnO, have been prepared by the one-step solid state reaction method at room temperature. The thermal decomposition processes taking place in the solid state oxalate mixture of nanometer CuC2O4-ZnC2O4·2H2O have been studied in static air using TG, DSC, XRD and TEM techniques. TEM showed that the grain size of the decomposition product is 5-15 nm. The values of the activation energy Eα were determined using the isoconversional procedure of KAS method and the Ozawa method. The most possible mechanism function f（α） of the thermal decompositions of nanosized CuC2O4-ZnC2O4·2H2O are defined using the comparative method, function models of tbe decomposition of CuC2O4 and ZnC2O4, follow tbe same mechanism function ＂Avrami-Erofeev equalion＂. The pre-exponential factor A is obtained on the basis of Eα and f（α）, thus the thermal analysis kinetic triplet of the decompositions of nanosized CuC2O4-ZnC2O4·2H2O are determined.

Precipitation of flaky moolooite and its thermal decomposition

Moolooite particles with flaky morphology were synthesized by mixing dilute solutions of copper nitrate and sodium oxalate in the presence of citric acid. Solution p H value, citric acid concentration, and stirring were found to have large effect on the shape of the precipitated particles. Under the stirring, the radial area of flaky moolooite particles was enlarged and extended to become a thinner and larger flake. This is ascribed to growth promotion caused by the selective absorption of citric ligands onto a particular crystalline surface of the moolooite particles. Flaky shape of the moolooite particles tended to become spherical and disappeared completely when decomposed under an Ar atmosphere, leading to the formation of large porous aggregated particles composed of many tiny nanosized copper crystals.

Cu/Cu2O nanostructures derived from copper oxalate as high performance electrocatalyst for glucose oxidation

Porous nanomaterials are classified as a kind of materials with great potential for development in the field of electrocatalysis,but there is still room for further improve ment as catalysts.We develop a threedimensional(3D)porous structure of Cu/Cu2O as an electrocatalyst for the glucose oxidation reaction(GOR)using the method of calcining the precursor CuC2O4·2H2O in N2.The obtained porous Cu/Cu2O nanostructure can provide more opportunities for effective reactions between particles,which can explain their efficient electrocatalytic performance.Additionally,the as-synthesized Cu/Cu2O nanostructure exhibits outstanding electrocatalytic performance for the glucose,including good stability,excellent sensitivity and remarkable selectivity.