Increasing reaction temperature produces photoluminescent polymer nanodots (PPNDs) with decreased particle size and increased quantum yield. Such PPNDs are used as an effective fluorescent sensing platform for label-free sensitive and selective detection of Cu(II) ions with a detection limit as low as 1 nM. This method is successfully applied to determine Cu(2+) in real water samples.

The present article reports on a simple, economical, and green preparative strategy toward water-soluble, fluorescent carbon nanoparticles (CPs) with a quantum yield of approximately 6.9% by hydrothermal process using low cost wastes of pomelo peel as a carbon source for the first time. We further explore the use of such CPs as probes for a fluorescent Hg(2+) detection application, which is based on Hg(2+)-induced fluorescence quenching of CPs. This sensing system exhibits excellent sensitivity and selectivity toward Hg(2+), and a detection limit as low as 0.23 nM is achieved. The practical use of this system for Hg(2+) determination in lake water samples is also demonstrated successfully.

Developing non-noble-metal hydrogen evolution reaction electrocatalysts with high activity is critical for future renewable energy systems. The direct growth of active phases on current collectors not only eliminates using polymer binder but also offers time-saving preparation of electrode. In this Letter, we develop self-supported FeP nanorod arrays on carbon cloth (FeP NAs/CC) via low-temperature phosphidation of its Fe 2 O 3 NAs/CC. As a novel 3D hydrogen evolution cathode in acidic media, the FeP NAs/CC exhibits high catalytic activity and only needs an overpotential of 58 mV to afford current density of 10 mA/cm 2 . This electrode also works efficiently in both neutral and alkaline solutions.