Meng-Ke Wu

MOF-derived self-sacrificing route to hollow NiS2/ZnS nanospheres for high performance supercapacitors

Transition metal sulfides have complex valence states and exhibit excellent properties and promising applications in supercapacitors. NiS2/ZnS hollow spherical nanocomposites have been successfully synthesized via a facile MOF-derived self-sacrificing route. The synthesis process involves solvothermal method for preparation of Ni/Zn–BDC MOF and subsequently chemical sulfidation treatment to convert into NiS2/ZnS hollow nanospheres. When evaluated as electrode materials in supercapacitor, the NiS2/ZnS hollow nanospheres exhibit high capacitance of 1198 F g−1 at the current density of 1 A g−1. Moreover, an asymmetric supercapacitor based on NiS2/ZnS hollow nanospheres as the positive electrode and activated carbon (AC) as the negative electrode achieves an energy density of 28.0 W h kg−1 at a power density of 478.9 kW kg−1. The results suggest the NiS2/ZnS hollow nanospheres are promising electrode materials for high-performance supercapacitors.

Enhanced photocatalytic performance of BiOBr/NH2-MIL-125(Ti) composite for dye degradation under visible light.

Metal-organic frameworks (MOFs) are considered as suitable materials for various applications in the area of photocatalysis. On the other hand, 2D BiOBr materials are efficient for the photodegradation of organic dyes under visible light illumination. In this work, BiOBr/NH2-MIL-125(Ti) composite photocatalysts with different NH2-MIL-125(Ti) content were prepared by incorporating NH2-MIL-125(Ti) with BiOBr using a co-precipitation method. A series of characterizations confirmed the strong synergistic effect between BiOBr and NH2-MIL-125(Ti). In rhodamine B (RhB) degradation experiments, the composite photocatalyst with a mass percent of 7 wt% NH2-MIL-125(Ti) exhibited an improved photocatalytic activity compared to pristine BiOBr and NH2-MIL-125(Ti). Furthermore, the enhanced photocatalytic performance under visible light illumination could be attributed to the Ti3+-Ti4+ intervalence electron transfer and synergistic effect between NH2-MIL-125(Ti) and BiOBr, and also resulted in a separation efficiency of photo-generated electron-hole pairs during the photocatalytic reaction. This study can open up numerous opportunities for the development of various MOF-based visible light photocatalysts when combined with 2D bismuth oxyhalide materials for applications in environmental cleaning.

Hierarchical Two-Dimensional Conductive Metal–Organic Framework/Layered Double Hydroxide Nanoarray for a High-Performance Supercapacitor

A novel hierarchical nanoarray material based on a two-dimensional metal-organic framework (Ni-CAT) and a layered double hydroxide (NiCo-LDH) was fabricated on a nickel foam substrate. By taking advantage of the regular nanostructure and making full use of the high porosity and excellent conductivity, the hybrid material exhibits a high areal capacitance for a supercapacitor (3200 mF cm-2 at 1 mA cm-2).