Search

Selective detection of dopamine is still a challenge due to the strong interference from ascorbic acid (AA). A hybrid dopamine electrochemical sensor was fabricated by boron-doped diamond (BDD) film co-modified with gold nanoparticles and graphite-coated nickel nanoparticles (Au-C@Ni/BDD). Highly sensitive and selective detection toward dopamine was achieved by multiple electrochemical anodic polarization treatment (EAPT) with relatively mild voltage (+ 1.6 V vs. Ag/AgCl) on Au-C@Ni/BDD electrode. Specifically, the oxidation peak separation between ascorbic acid and dopamine reached 166 mV, and the limit of detection of dopamine was as low as 0.015 μM in a linear concentration range of 0.05–100 μM with the sensitivity up to 1.99 μA μM−1 cm−2 even in the presence of interference of high-level AA. These could be ascribed to the electrocatalytically active sites and functional oxygen-containing groups of the hybrid electrodes produced by the EAPT and the excellent catalytical activity of gold nanoparticles.

In vivo tracking or in vitro real sample analysis by electrochemistry is one of the most straight and useful methods in biosensor field. However, surface biofouling of electrodes by non-specific protein adsorption is inevitable and usually leads to a decrease in sensitivity. Here, we developed a Nafion-coated porous boron-doped diamond (NAF/pBDD) electrode with hydrophobic nanostructures to minimize the biofouling effect and selectively detect dopamine (DA). Larger active area was obtained by this procedure compared to a bare diamond electrode. The as-prepared electrode shows excellent antifouling property and enrichment capacity toward selective detection of dopamine (DA). The low background current of the BDD electrode and the enhanced signals enables a lower detection limit, 42 nmol L−1, and a wider linear range, 0.1–110 μmol L−1, for determination of DA in human serum. Additionally, the facile modified electrode demonstrated renewable property and long-term stability due to the fact that the antifouling nanostructures belong to its own.

This communication reports nickel hydroxide nanoplates grown on nickel foam (NF) by one-step water bath treatment of NF in nitric acid solution. The reaction temperature and duration were critical to the formation of nanoplates. Moreover, the Ni(OH)2 electrode on nickel foam (Ni(OH)2/NF) exhibited high performance and prominent stability toward the hydrogen evolution reaction (HER) in an alkaline solution. The mentioned finding will be expected to broaden the development of Ni(OH)2-based binder-free electrodes for electrochemical applications.

The performance of the electrochemical advanced oxidation process (EAOP) is usually hindered by the structure of electrode and the production of hydroxyl radical (·OH). Here, a novel 3D boron-doped diamond (3D-BDD) anode was successfully developed through metal printing and chemical vapor deposition. The designed 3D-BDD EAOP system could produce more reactive ·OH and decompose different organic compounds more efficiently, displaying lower energy consumption and higher color and total organic carbon removal compared to conventional 2D-BDD electrode. The computational fluid dynamics (CFD) calculation demonstrated the intrinsic through-holes on the BDD electrode could promote the mass transfer of chemical substances, and the electron spin resonance (ESR) measurement indicated more ·OH were generated on 3D-BDD. This is the first demonstration of 3D printing employed in the synthesis of BDD anodes for organic compounds removal, which gives a perspective insight into batch fabrication of customized, rationally-designed BDD anodes with controllable geometries and sizes.

Increasing energy demands have accelerated the exploration of renewable energy, and H2 is a promising substitute for nonrenewable energy sources. The electrocatalytic hydrogen evolution reaction (HER) is a convenient, stable, and eco-friendly route for producing hydrogen whose performance can be enhanced via the rational structure design of catalysts and the replacement of the anodic oxygen evolution reaction (OER) with the urea oxidation reaction (UOR). Herein, 3D hierarchically structured NiMo microrod arrays was constructed on Ni foam where ZnO served as core and support (NiMo@ZnO/NF), which showed a high activity when used as a bifunctional electrocatalyst for the HER and UOR. It only required potentials of −110 mV and 1.405 V to deliver a current density of 10 mA cm−2 towards HER and UOR, respectively. NiMo@ZnO/NF was used as both the anode and cathode to construct a symmetric electrolyzer that was used for water splitting and urea electrolysis. The cell voltage decreased from 1.718 V to 1.549 V at 10 mA cm−2 after substituting the OER with UOR. Finally, the coupled NiMo@ZnO/NF || NiMo@ZnO/NF system can be driven by an AA battery in an alkaline solution containing urea, which demonstrates a practical and effective method for producing hydrogen assisted by anodic urea oxidation.