Design of Cadmium Hydroxyapatite Hierarchical Structures with Adjustable Morphology by a Template-free Hydrothermal Route

Cadmium hydroxyapatite（Cd-Hap） hierarchical structures with novel morphologies were successfully synthesized via a simple template-free and mild hydrothermal method. By properly monitoring the initial pH value of the reaction solutions, the morphology of the Cd-Hap crystals could be tuned to be bunch-like（consist of nanosized cuboids）, quasi peanut-like（consist of nanoparticles） and flower-like（consist of assembled bundles units）. On the basis of a series of contrast experiments over time, the probable growth mechanism and fabrication process of the products were proposed. The optical and photocatalytic properties of the obtained Cd-Hap hierarchical structures were firstly investigated. The results showed that pure Cd-Hap could only absorb UV light with wavelength shorter than -350 nm while hydroxyapatite supported Ag3PO4 composites showed a pronounced photocatalytic activity upon decomposition of methyl orange dye in aqueous solution under visible light irradiation. The support of hydroxyapatite can also greatly reduce the cost of expensive Ag3PO4 photocatalysts in practical applications.

Electrocatalytic N_(2) reduction to NH3 with high Faradaic efficiency enabled by vanadium phosphide nanoparticle on V foil

To develop highly efficient electrochemical catalysts for N2 fixation is important to sustainable ambient NH_(3) production through the N_(2) reduction reaction(NRR).Herein,we demonstrate the development of vanadium phosphide nanoparticle on V foil as a high-efficiency and stable catalyst for ambient NH3 production with excellent selectivity.The high Faradaic efficiency of 22%with a large NH3 yield of 8.35×10^(−11) mol·s^(−1)·cm^(−2)was obtained at 0 V vs.the reversible hydrogen electrode in acid solution,superior to all previously studied V-based NRR catalysts.Density functional theory calculations are also utilized to have an insight into the catalytic mechanism.

In situ growth of polydopamine on surface of covalent organic frameworks under the catalysis of acid phosphatase for dopamine detection

Dopamine(DA)is easy to be oxidized and polymerizes to form polydopamine(pDA)in alkaline conditions,while the synthesis is usually time-consuming(48 h).Herein,the polymerization of DA is completed with 4 h under the catalysis of acid phosphatase(ACP).The high efficiency makes the detection of DA feasibility based on the self-polymerization of DA.In this assay,pDA is grown in situ on the surface of covalent organic frameworks(COFs),and then the fluorescence of COFs is quenched significantly.The linear range of DA is achieved from 0.5-50μmol/L with a detection limit of 0.16μmol/L.The detection of DA is not interfered with uric acid,ascorbic acid,and some phenolic compounds,because these substances cannot polymerize in the presence of ACP.Moreover,benefiting from the good sensitivity and selectivity,DA has been successfully determined by this strategy in human urine samples with satisfactory recoveries.