Accurate thermometry at micro- and nanoscales is essential in many nanobiotechnological applications. The nanothermometers introduced in this paper are composed of labeled molecular beacons (MBs) comprising gold nanoparticles (AuNPs) on which, depending on application, many MBs of one or more types are immobilized. In this design, three differently labeled MBs with different thermostabilities function as the sensing elements, and AuNPs act as carriers of the MBs and also quenchers of their fluorophores. This flexible design results in a number of nanothermometers with various temperature-sensing ranges. At the lowest temperature, the MBs are in the closed form, where they are quenched. By increasing the temperature, the MBs start to open with respect to their melting points (Tm), and as a result, the fluorescence emission will increase. The temperature resolution of the nanoprobes over a range of 15-60 °C is less than 0.50 °C, which indicates their high sensitivity. Such a good temperature resolution is a result of the specific design of the unusual less stable MBs and also presence of many MBs on AuNPs. The reproducibility and precision of the probes are also satisfactory. The multiplex MB nanoprobe is suitable for thermal imaging by fluorescence microscopy.

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The electrochemical water-oxidation reaction usually requires a catalyst to reduce the overpotential and Earth-abundant catalysts, like MnO2, are attracting much attention. Here we use chemometric analysis, EPR and UV-Vis spectroscopies to track Mn(II) and MnO4(-) byproducts to the reaction of a MnO2 film in the presence of cerium(IV) ammonium nitrate. Permanganate ion is involved in at least two key reactions: it may oxidize water to O2 or can combine with Mn(II) to remake MnO2 solid. We propose mechanisms for water oxidation and present a self-healing process for this reaction.

In this report, Fe3O4 nanoparticles are modified for the first time with graphene quantum dots (GQD) and used for the stabilization of PdCu bimetallic nanoparticles. The new magnetic compound, PdCu@GQD@Fe3O4, is characterized by different methods such as SEM, high‐resolution (HR)‐TEM, energy‐dispersive X‐ray spectroscopy (EDS) mapping, XRD, and X‐ray photoelectron spectroscopy (XPS). This material is applied as an efficient catalyst for the Sonogashira reaction of aryl iodides, bromides, and chlorides in toluene or N,N‐dimethylacetamide at 60–110 °C in very high yields with 0.3 mol % of Pd loading. According to different tests, such as polyvinylpyridine poisoning, hot filtration, and kinetic studies, this catalyst works under heterogeneous conditions. By magnetic separation of the catalyst, it can be recycled for six consecutive runs with only a small decrease in activity without appreciable structural modification of the reused catalyst, which is characterized by TEM and XPS.

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