Nanocrystals of CuCoO2 derived from MOFs and their catalytic performance for the oxygen evolution reaction.

In this work, two different solvothermal synthesis routes were employed to prepare MOF-derived CuCoO2 (CCO) nanocrystals for electrocatalytic oxygen evolution reaction (OER) application. The effects of the reductants (ethylene glycol, methanol, ethanol, and isopropanol), NaOH addition, the reactants, and the reaction temperature on the structure and morphology of the reaction product were investigated. In the first route, Cu-BTC derived CCO (CCO1) nanocrystals with a size of ∼214 nm and a specific surface area of 4.93 m2 g-1 were prepared by using Cu-BTC and Co(NO3)2·6H2O as the Cu and Co source, respectively. In the second route, ZIF-67 derived CCO (CCO2) nanocrystals with a size of ∼146 nm and a specific surface area of 11.69 m2 g-1 were prepared by using ZIF-67 and Cu(NO3)2·3H2O as the Co and Cu source, respectively. Moreover, the OER performances of Ni foam supported CCO1 (Ni@CCO1) and CCO2 (Ni@CCO2) electrodes were evaluated in 1.0 M KOH solution. Ni@CCO2 demonstrates a better OER catalytic performance with a lower overpotential of 394.5 mV at 10 mA cm-2, a smaller Tafel slope of 82.6 mV dec-1, and long-term durability, which are superior to those of some previously reported delafossite oxide or perovskite oxide catalysts. This work reveals the preparation method and application potential of CCO electrocatalysts by using Cu-BTC/ZIF-67 as the precursor, providing a new approach for the preparation of delafossite oxide CCO and the enhancement of their OER performances.

Effect of nickel doping on the structure, morphology and oxygen evolution reaction performance of Cu-BTC derived CuCoO2.

In this work, nickel (Ni) doped Cu-BTC derived CuCoO2 (CCO) was successfully synthesized by a solvothermal method, and the effects of Ni doping concentration (such as 1 at%, 3 at% and 5 at%) on the crystal structure, morphology, composition and oxygen evolution reaction (OER) catalytic performance of CuCoO2 were investigated. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) were carried out to characterize the crystal structure, morphology and chemical composition of CuCoO2 crystals. The results show that Ni ions have been successfully doped into the CuCoO2 crystal structure and this Ni introduction can reduce its grain size, and 5 at% Ni doped CCO (5NCCO) nanosheets exhibit an average particle size of 386 nm with thicknesses around 28 nm. The optimal Ni@5NCCO electrode needs an overpotential of 409 mV to generate a current density of 10 mA cm-2 and is able to sustain galvanostatic OER electrolysis for 18 hours with only a minor degradation of 30 mV. The enhanced OER performance may be due to the increase in the catalytic activity area and the improvement in conductivity, which is caused by a decrease in grain size and the formation of a porous structure for Ni doped Cu-BTC derived CuCoO2.

Evaluation of bioactive glass scaffolds incorporating SrO or ZnO for bone repair: In vitro bioactivity and antibacterial activity.

A series of bioactive glass scaffolds doped with SrO or ZnO (0, 5, and 10 mol%) were synthesized by the foam replica and melting method. The thermodynamic evolution, phase composition, microstructure, ion release, in vitro bioactivity, and oxygen density of the scaffolds were characterized. The proliferation of murine long bone osteocyte Y4 cells was studied by cell culture. The survival rate of the BGs evaluated the antibacterial activity and Escherichia coli strains in co-culture. The results indicated that the process window decreases with the increase of dopants. All the samples have a pore structure size of 200-400 µm. When the scaffolds were immersed in simulated body fluid for 28 days, hydroxyapatite formation was not affected, but the degradation process was retarded. The glass network packing and ionic radii variations of the substitution ions control surface degradation, glass dissolution, and ion release. MTT results revealed that 5Sr-BG had a significant effect on promoting cell proliferation and none of the BGs were cytotoxicity. Sr-BGs and Zn-BGs exhibited significantly inhibited growth against E. coli bacterial strains. Generally, these results showed the 5Sr-BG scaffold with high vitro bioactivity, cell proliferation, and antibacterial property is an important candidate material for bone tissue regeneration and repair.

Influence of the slight adjustment of oxides on the structural and physico-chemical properties of thin film transistor-liquid crystal display substrate glass.

By the slight adjustment of oxides constituting thin film transistor-liquid crystal display (TFT-LCD) substrate glass, including equal mole fraction substitution of Al2O3, GeO2, B2O3, P2O5 and ZrO2 for SiO2, as well as the substitution of CaO for SrO with the total contents unchanged, the structural and physico-chemical properties of the glass was investigated by Raman spectroscopy and other measurements. The results showed that the short-range disorder brought by the substitution of GeO2, B2O3 and P2O5 for SiO2 could weaken the stability and compactness of the glass network, and the physico-chemical properties deteriorated, while the process of glass melting would become easier accordingly. The short-range disorder by the substitution of ZrO2 for SiO2 with 1% mole fraction showed a little difference with other samples. Finally, the substitution of modified cations, such as CaO and SrO, showed a smaller variation compared with the substitution of network formers. On the condition of 1% mole fraction substitution of oxides investigated, the variation of samples showed a reasonable change and the performance was basically all satisfied for the use of TFT-LCD substrate.