Wenchi Zhang

One-Pot Anchoring of Pd Nanoparticles on Nitrogen-Doped Carbon through Dopamine Self-Polymerization and Activity in the Electrocatalytic Methanol Oxidation Reaction

Exploration of advanced electrocatalysts to promote the sluggish methanol oxidation reaction (MOR) is of vital importance for developing high efficiency and low-cost direct methanol fuel cells. Highly dispersed palladium nanoparticles (Pd NPs) anchored on a nitrogen-doped carbon support were fabricated using a facile one-pot dopamine self-polymerization mediated redox strategy, in which dopamine not only acted as a moderate reductant to induce the formation of Pd NPs during self-polymerization but was also the precursor of the nitrogen-doped carbon support for Pd. The synthesized hybrid features the following characteristics: 1) High dispersity of Pd NPs, which exposed a high abundance of active surfaces and sites for heterogeneous electrocatalysis; 2) metal-support interactions, which may affect the surface chemistry and electron distribution of active Pd NPs; 3) the Pd NPs were partially imbedded or encapsulated into the support, thus reducing the possible agglomeration of Pd NPs during cyclic measurements. The electrocatalyst with such favorable features provided higher mass activity (2.2 times that of commercial Pd/C) and better durability (reduced loss of activity during simulated frequent startup-shutdown operations) for the MOR in alkaline media.

A molecularly-imprinted-electrochemical-sensor modified with nano-carbon-dots with high sensitivity and selectivity for rapid determination of glucose

In this work, a novel molecularly imprinted electrochemical sensor (MIECS) based on a glassy carbon electrode (GCE) modified with carbon dots (CDs) and chitosan (CS) for the determination of glucose was proposed for the first time. The use of the environmental-friendly CDs and CS as electrode modifications improved the active area and electron-transport ability substantially, while 3-aminobenzeneboronic acid was used as a functional monomer and glucose as template for the fabrication of molecularly imprinted polymer (MIP) film to detect glucose via differential pulse voltammetry. Transmission electron microscope, Fourier transform infrared spectroscopy, energy dispersive x-ray spectrometry, cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were applied to characterize the fabricated sensor. Experimental conditions such as molar ratio of functional monomer to template, volume ratio of CDs to CS, incubation time and elution time were optimized. By using glucose as a model analyte, the MIECS had two assay ranges of 0.5-40 μM and 50-600 μM, and fairly low limit of detection (LOD) of 0.09 μM (S/N = 3) under the optimized conditions. The MIECS also exhibited excellent selectivity, good reproducibility, and stability. The proposed sensor was successfully applied to a preliminary test for glucose analysis in real human blood serum samples.