Publications

Engineering core-shell materials with rationally designed architectures and components is an effective strategy to fulfill the high-performance requirements of supercapacitors. Herein, hierarchical candied-haws-like NiCo2S4NiCo(HCO3)2 core-shell heterostructure (NiCo2S4@HCs) is designed with NiCo(HCO3)2 polyhedrons being tightly strung by cross-linked NiCo2S4 nanowires. This rational design not only creates more electroactive sites but also suppresses the volume expansion during the charge-discharge processes. Meanwhile, density functional theory calculations ascertain that the formation of NiCo2S4@HCs heterostructure simultaneously facilitates OH− adsorption/desorption and accelerates electron transfer within the electrode, boosting fast and efficient redox reactions. Ex situ X-ray diffraction and Raman measurements reveal that gradual phase transformations from NiCo(HCO3)2 to NiCo(OH)2CO3 and then to highly-active NiCoOOH take place during the cycles. Therefore, NiCo2S4@HCs demonstrates an ultrahigh capacitance of 3178.2 F g−1 at 1 A g−1 and a remarkable rate capability of 2179.3 F g−1 at 30 A g−1. In addition, the asymmetric supercapacitor NiCo2S4@HCs//AC exhibits a high energy density of 69.6 W h kg−1 at the power density of 847 W kg−1 and excellent cycling stability with 90.2% retained capacitance after 10 000 cycles. Therefore, this novel structural design has effectively manipulated the interface charge states and guaranteed the structural integrity of electrode materials to achieve superior electrochemical performances.

Wide-spectrum light harvesting is critical in determining practical photocatalysis water splitting. Hybridization presents a viable strategy to broaden photocatalytic capability, yet the direct conversion of near-infrared (NIR) light remains a matter of great concern. Herein, a state-of-art ternary Au nanorodsMoS2-CdS (AMC) hybrid is designed to address this challenge. AMC achieves a leap-forward apparent quantum yield (AQY) of 1.06% at 700 nm and an AQY of 35.7% at 450 nm, extending the hydrogen evolution reaction (HER) capability of CdS hybrids to the NIR region firstly. It is revealed that the energetic hot electrons supplied by Au nanorods (NRs) are responsible for this extension. Indispensable, MoS2 performs a platform to collect the hot electrons from Au NRs and the photoinduced electrons from CdS. The HER active sites are positioned as MoS2-CdS interfaces both from experimental and theoretical viewpoints. This work opens up a new horizon for the forward of the wide-spectrum photocatalysis design.

Dialysis diffusion kinetics are investigated via in situ NMR spectroscopy for numerous different raw polymeric solutions to result in a general guideline for polymer purification using dialysis. In several approaches, a polymer was on purpose contaminated with its respective monomer, regenerated conducting conventional dialysis and monitored online utilizing in situ NMR spectroscopy. Consequently, polymer type and molar mass, monomer type, molar mass cut-off of the dialysis tubing and type of solvent were varied resulting in 29 different purification approaches and over 40 000 NMR-spectra. As a result, several major parameters were identified affecting the purification process significantly such as the chosen solvent, viscosity and alpha value. On the contrary, parameters such as dialysis tubing molar mass cut-off and molar mass of the polymer did not affect the purification in a significant manner. Furthermore, physical properties such as density, viscosity, alpha value, and dipole moment of the ingredients were combined in a principal component analysis in order to identify the most important parameters.