The monitoring of nitroaromatic explosives plays a vital role in homeland security and public safety. In this work, by employing allylamine as the source for both carbon and nitrogen, photoluminescent nitrogen-rich carbon nanodots (NC-dots) were prepared via a peaceable and inexpensive hydrothermal route for the first time. The average size of the present synthesized NC-dots is 2.88 ± 0.4 nm. The NC-dots show outstanding blue fluorescence and exhibit a dramatically high fluorescence quantum yield of 15%. The NC-dots were completely characterized using various techniques. The NC-dots could be employed as a fluorescent material for the sensing of TNP with distinguished selectivity. The addition of TNP into the NC-dots resulted in splendid quenching, which was ascribed to the integrative action of fluorescence resonance energy transfer, electron transfer, and the hydrogen-bond interactions between NC-dots and TNP. In parallel, the proposed NC-dots could be applied as a new type of fluorescent ink. In addition, a detailed mechanism for the production of NC-dots via self-polymerization and carbonization was proposed.

No abstract

It is well known that microorganisms tend to form biofilms on metal surfaces to accelerate/decelerate corrosion and affect their service life. Bacillus subtilis was used to produce a dense biofilm on an AZ31B magnesium alloy surface. Corrosion behavior of the alloy with the B. subtilis biofilm was evaluated in artificial seawater. The results revealed that the biofilm hampered extracellular electron transfer significantly, which resulted in a decrease of icorr and increase of Rt clearly compared to the control group. Moreover, an ennoblement of Ecorr was detected under the condition of B. subtilis biofilm covering. Significant reduction of the corrosion was observed by using the cyclic polarization method. All of these prove that the existence of the B. subtilis biofilm effectively enhances the anti-corrosion performance of the AZ31B magnesium alloy. This result may enhance the usage of bio-interfaces for temporary corrosion control. In addition, a possible corrosion inhibition mechanism of B. subtilis on AZ31B magnesium alloy was proposed.

No abstract