Jingwen Ma

Polyaniline Derived N‐Doped Carbon‐Coated Cobalt Phosphide Nanoparticles Deposited on N‐Doped Graphene as an Efficient Electrocatalyst for Hydrogen Evolution Reaction

The development of highly efficient and durable non-noble metal electrocatalysts for the hydrogen evolution reaction (HER) is significant for clean and renewable energy research. This work reports the synthesis of N-doped graphene nanosheets supported N-doped carbon coated cobalt phosphide (CoP) nanoparticles via a pyrolysis and a subsequent phosphating process by using polyaniline. The obtained electrocatalyst exhibits excellent electrochemical activity for HER with a small overpotential of -135 mV at 10 mA cm-2 and a low Tafel slope of 59.3 mV dec-1 in 0.5 m H2 SO4 . Additionally, the encapsulation of N-doped carbon shell prevents CoP nanoparticles from corrosion, exhibiting good stability after 14 h operation. Moreover, the as-prepared electrocatalyst also shows outstanding activity and stability in basic and neutral electrolytes.

Preparation of Cuprous Oxide Mesoporous Spheres with Different Pore Sizes for Non-Enzymatic Glucose Detection

Mass transfer plays a significant role in a sensors performance, because the substrate can be detected only when it contacts with the active catalytic surface. In this work, cuprous oxide mesoporous nanospheres (Cu₂O MPNS) with different pore size distributions are fabricated and applied as electrocatalysts for glucose detection. The small pore Cu₂O (SP-Cu₂O, mean pore size of 5.3 nm) and large pore Cu₂O (LP-Cu₂O, mean pore size of 16.4 nm) spheres are prepared by the template method and an etching treatment. The obtained two kinds of Cu₂O MPNS exhibit high porosity with a similar specific surface area of 61.2 and 63.4 (m²·g-1), respectively. The prepared Cu₂O MPNS are used to construct an electrochemical non-enzymatic glucose sensor. The results show that the LP-Cu₂O exhibits better performance than SP-Cu₂O, which illustrates that the internal diffusion takes a great impact on the performance of the sensor. The LP-Cu₂O modified electrode possesses a high and reproducible sensitivity of 2116.9 μA mM-1·cm-2 at the applied potential of 0.6 V with a wide detection range of 0.003-7.8 mM and a low detection limit of 0.42 μM.

Magnetic Au-Ag-γ-Fe2O3/rGO Nanocomposites as an Efficient Catalyst for the Reduction of 4-Nitrophenol

In this paper, a facile route has been developed to prepare magnetic trimetallic Au-Ag-γ-Fe2O3/rGO nanocomposites. The impact of the preparation method (the intensity of reductant) on the catalytic performance was investigated. The nanocomposites were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The prepared nanocomposites show fine catalytic activity towards the reduction reaction of 4-nitrophenol (4-NP). The nanocomposites also have superparamagnetism at room temperature, which can be easily separated from the reaction systems by applying an external magnetic field.