Shengnan Sun

Reserving Interior Void Space for Volume Change Accommodation: An Example of Cable-Like MWNTs@SnO2@C Composite for Superior Lithium and Sodium Storage.

Reserving interior void space in the cable‐like structure of multiwalled carbon nanotubes‐in‐SnO2‐in‐carbon layer (MWNTs@SnO2@C) is reported for the first time. Such a design enables the structure performing excellent for Li and Na storage, which benefit from the good electrical conductivity of MWNTs and carbon layer as well as the reserved void space to accommodate the volume changes of SnO2.

A new insight into electrochemical detection of eugenol by hierarchical sheaf-like mesoporous NiCo2O4

NiCo2O4 nanosheets with sheaf-like nanostructure morphologies have been synthesized by a facile one-step hydrothermal reaction followed by annealing treatment. Impressively, the NiCo2O4 nanosheets exhibit rapid detection of eugenol. The linear range of detection is from 1–500 μM, and the limit of detection is 5.4 pM. The NiCo2O4 modified electrode demonstrated high sensitivity, good repeatability and reproducibility, and long-term stability (7% decrease in response over 30 days). Based on this work, an electrochemical reaction mechanism for eugenol oxidation was proposed, and in addition, the NiCo2O4 modified electrode was successfully employed for the analysis of eugenol in medicative balm samples. Recovery values for eugenol in medicative balm samples were in the range 98.7%–105.5%.

An electrochemical sensor highly selective for lindane determination: a comparative study using three different α-MnO2 nanostructures

Here we describe a simple, highly reproducible ultra-sensitive electrochemical sensor for lindane based on α-MnO2 nanostructures. The results showed that the α-MnO2 nanostructures effectively catalyzed the electrochemical reduction of lindane. A good linearity was obtained in the range of 1.1 to 510 μM with a detection limit of 114 nM. The proposed lindane sensor was successfully employed for the determination of lindane in tap water samples with good recoveries. Negligible amperometric currents are observed in the control experiments using triclosan (T), chlorobenzene (CB), benzene (B), 1,3,5-trichlorobenzene (1,3,5-TCB), and 4-chlorobenzaldehyde (4-CBA), suggesting a sensing specificity to lindane. The proposed sensor also exhibited good stability and reproducibility for lindane determination.

Enlarged CoO Covalency in Octahedral Sites Leading to Highly Efficient Spinel Oxides for Oxygen Evolution Reaction

Cobalt-containing spinel oxides are promising electrocatalysts for the oxygen evolution reaction (OER) owing to their remarkable activity and durability. However, the activity still needs further improvement and related fundamentals remain untouched. The fact that spinel oxides tend to form cation deficiencies can differentiate their electrocatalysis from other oxide materials, for example, the most studied oxygen-deficient perovskites. Here, a systematic study of spinel ZnFex Co2-x O4 oxides (x = 0-2.0) toward the OER is presented and a highly active catalyst superior to benchmark IrO2 is developed. The distinctive OER activity is found to be dominated by the metal-oxygen covalency and an enlarged CoO covalency by 10-30 at% Fe substitution is responsible for the activity enhancement. While the pH-dependent OER activity of ZnFe0.4 Co1.6 O4 (the optimal one) indicates decoupled proton-electron transfers during the OER, the involvement of lattice oxygen is not considered as a favorable route because of the downshifted O p-band center relative to Fermi level governed by the spinels cation deficient nature.