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To avoid aggregation in the production of the active electrode material, Ni–Zn system materials (NixZn1−xOH, NiO–ZnO and NixZn1−xS) were synthesized by using a belt reaction zone model, and then were characterized systematically in this work. Among these materials, NixZn1−xS porous spheroid nanoparticles with diameters ∼30 nm possess abundant interconnected micropores caused by the Kirkendall effect in the synthesis, leading to a high surface area of 148.4 m2 g−1 and special paths for ion diffusion. In the three-electrode system testing, NixZn1−xS porous spheroid nanoparticles show the highest specific capacitance of 1867 F g−1 at a current density of 1 A g−1, as well as excellent rate capability and cycling stability. Using NixZn1−xS as the positive electrode and active carbon as the negative electrode, the asymmetric supercapacitor device exhibits an excellent electrochemical performance. The results provide us with a modified method to synthesize metal hydroxides, oxides and sulfides, in order to obtain materials with high supercapacitor performance.

Nanostructured Bi–Bi2O2CO3–ZnO composites were successfully prepared through a facile one-step hydrothermal method. The composite was constructed by ZnO nanorods with a diameter of 30–40 nm embedded in Bi2O2CO3 platelets with a small quantity of Bi particles dispersed on the platelets, which further assembled into micron clusters. The photocatalytic performance of the composite was evaluated by the degradation of methyl orange and phenol under UV and visible light irradiation, respectively. The results revealed that the composites showed enhanced photocatalytic activity in comparison with either ZnO or Bi2O2CO3, and the Bi–Bi2O2CO3–ZnO photocatalyst with 20 mol% of Bi2O2CO3 exhibited the best photocatalytic efficiency. The reusability test explored the reliable stability and reusability for industrial applications, which was endowed by the special feature of nanostructured micron clusters. The superior photocatalytic activity could be attributed to the heterojunction interfaces and compound band gap structure which facilitated the separation of the photo-generated electrons and holes at the interface and promoted an effective charge transfer path. Additionally, the existing metal Bi also acted as electron traps to manifest a positive effect. The present study might give an insight into the design of novel heterostructured materials for the light harvesting related environment management and energy conversion applications.

Biocompatible coatings, such as calcium phosphate (CaP), have been applied on biodegradable magnesium and its alloy to control their rapid degradation rates. This paper reports a further enhancement to the CaP coating performance by applying a simple fluorine post-treatment on a CaP coating to form an F–CaP composite coating. The CaP coating was first deposited on AZ60 magnesium alloy samples via a phosphating method, then subjected to different post-treatment solutions to obtain F–CaP composite coatings. The effects of pH and post-treatment time were analyzed and the optimal corrosion resistance was obtained at pH 12 for 2 h. The F–CaP coating consisted of mainly fluoridated hydroxyapatite, tricalcium phosphate and magnesium fluoride. An electrochemical corrosion measurement in simulated body fluid revealed that the polarization resistance of the F–CaP coating is about 3 and 26 times higher than those of the HA and CaP coatings, respectively, due to its denser coating structure and smoother surface. During immersion tests, the F–CaP coating also exhibited an improved corrosion resistance with more active biomineralization than the CaP and HA coatings. This fluorine post-treatment offers a novel practical approach in improving the biodegradation behavior of CaP coatings on biodegradable magnesium implants.