Increasing energy demands and environment awareness have promoted extensive research on the development of alternative energy conversion and storage technologies with high efficiency and environmental friendliness. Among them, water splitting is very appealing, and is receiving more and more attention. The critical challenge of this renewable-energy technology is to expedite the oxygen evolution reaction (OER) because of its slow kinetics and large overpotential. Therefore, developing efficient electrocatalysts with high catalytic activities is of great importance for high-performance water splitting. In the past few years, much effort has been devoted to the development of alternative OER electrocatalysts based on transition-metal elements that are low-cost, highly efficient, and have excellent stability. Here, recent progress on the design, synthesis, and application of OER electrocatalysts based on transition-metal elements, including Co, Ni, and Fe, is summarized, and some invigorating perspectives on the future developments are provided.

Highly efficient visible-light-driven g-C3N4/Ag2O heterostructured photocatalysts were prepared by a simple liquid phase synthesis method at room temperature. The composition, structure, morphology, and optical absorption properties of the as-prepared g-C3N4/Ag2O composites were characterized by XRD, FTIR, XPS, TEM, and UV-vis DRS, respectively. We found interestingly that the photogenerated charge carriers separations of the as-prepared g-C3N4/Ag2O composites were closely related to the mass ratio of g-C3N4 and Ag2O. When the mass ratio of g-C3N4 and Ag2O reached 1:4, the as-prepared composite exhibited the highest photocatalytic activity, which was almost 11 and 1.2 times as high as that of individual g-C3N4 and Ag2O, respectively. The enhancement of photocatalytic activity could be attributed to the synergetic effects between g-C3N4 and Ag2O as well as the improved dispersibility and the decreased particle size of Ag2O. Moreover, the as-prepared composites showed excellent stability toward the photodegradation of methyl orange (MO). Finally, a possible photocatalytic and charge separation mechanism was proposed.

Metal nanoclusters have received considerable interest due to their unique properties and potential applications in numerous fields. Particularly, newly emerging Cu nanoclusters offer excellent potential as functional biological probes. In this work, we for the first time report that the fluorescence of DNA-hosted Cu nanoclusters is very sensitive to base type located in the major groove. This intriguing finding provides a sensitive fluorimetric diagnostic of the mismatch type in a specific DNA sequence, which is difficult to achieve by traditional methods. Furthermore, the research results have shed some light on the luminescent mechanism of Cu nanoclusters. Owing to its high specificity and easy operation without rigorously controlled temperature and arduous probe DNA design, it is expected that the proposed procedure can provide a tool for early diagnosis and risk assessment of malignancy.

In this paper, a stable and highly efficient plasmonic photocatalyst, Ag@AgCl, with cube-like morphology, has been successfully prepared via a simple hydrothermal method. Using methylene dichloride as chlorine source in the synthesis can efficiently control the morphology of Ag@AgCl, due to the low release rate of chloride ions. Scanning electron microscopy (SEM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectra were used to characterize the obtained product. The photocatalytic activity of the obtained product was evaluated by the photodegradation of methyl orange (MO) under visible light irradiation, and it was found, interestingly, that Ag@AgCl exhibits high visible light photocatalytic activity and good stability.