Sandwich-Type Electrochemiluminescence Immunosensor Based on CDs@dSiO2 Nanoparticles as Nanoprobe and Co-Reactant.

In general, co-reactants are essential in highly efficient electrochemiluminescence (ECL) systems. Traditional co-reactants are usually toxic, so it is necessary to develop new environmentally friendly co-reactants. In this work, carbon dots (CDs) were assembled with dendritic silica nanospheres (CDs@dSiO2 NPs) to form a co-reactant of Ru(bpy)32+. Subsequently, a sandwich immunosensor for detecting human chorionic gonadotropin (HCG) was constructed based on CDs@dSiO2 NPs as co-reactants, the nanoprobe loaded with the secondary antibody, and Ru(bpy)32+ as a luminophore. In addition, compared to directly as a signal probe, the luminophore Ru (bpy)32+ as a part of the electrolyte solution is simpler in this work. The immunosensor has an extremely low limit of detection of 0.00019 mIU/mL. This work describes the synthesis of low-toxic, efficient, and environmentally friendly CDs, which have become ideal co-reactants of Ru(bpy)32+, and proposes an ECL immunosensor with excellent stability and selectivity, which has great potential in clinical applications.

CoNi Nanoparticles Supported on N-Doped Bifunctional Hollow Carbon Composites as High-Performance ORR/OER Catalysts for Rechargeable Zn-Air Batteries.

Searching for high-quality air electrode catalysts is the long-term goal for the practical application of Zn-air batteries. Here, a series of coexistent composite materials (CoNi/NHCS-TUC-x) of cobalt-nickel supported on nitrogen-doped hollow spherical carbon and tubular carbon are obtained using a simple pyrolysis strategy. Co and Ni in the composites are mainly present in the form of alloy nanoparticles, M-Nx and M-Cx (M = Co or Ni) species, with high oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) electroactivity. The materials containing different proportions of spherical carbon and tubular carbon obtained by simply adjusting the raw materials for generating tubular carbon exhibit interesting bifunctional performance: samples with an abundant tubular content have the highest ORR onset potential (0.91 V vs reversible hydrogen electrode), while those with a rich spherical content have the highest ORR current density (5.13 mA·cm-2). Furthermore, CoNi/NHCS-TUC-3 provides the lowest potential difference (ΔE = Ej=10 - E1/2) of 0.806 V. We then test the potential possibility of CoNi/NHCS-TUC-3 as an air electrode for primary and rechargeable Zn-air batteries. The primary battery delivers an open-circuit potential of 1.59 V, a peak power density of 361.8 mA·cm-2, and a specific capacity of 756.5 mA h·gZn-1. The rechargeable battery could be cycled stably for more than 55 h at 10 mA·cm-2. These characteristics make CoNi/NHCS-TUC-3 a superior electrocatalyst for both the ORR and OER, as well as a suitable bifunctional electrode applied to a rechargeable Zn-air battery.