Pd(Xantphos)Cl₂ has been identified as an efficient catalyst for the direct carbonylation of allylamines via C–N bond activation.

The reduction of Cu(OH)₂ by hydrazine in a concentrated NaOH solution containing ethylenediamine at 70 °C has been employed to prepare Cu nanowires. The net change during nanowire synthesis is that the consumption of Cu(OH)₂ and hydrazine gives rise to the formation of Cu nanowires, N₂ and H₂O, which make it possible for us to endlessly reuse the produced wastewater after the removal of Cu nanowires. By controlling the re-added amounts of hydrazine and ethylenediamine in the case of reusing the wastewater, we have found that the morphology of Cu nanowires is kept almost unchanged even though the wastewater is recycled more than ten times. The recycle of the endlessly reusable wastewater not only significantly reduces the cost of Cu nanowires but also makes this approach environmentally friendly. In addition, as a catalyst for selective hydrogenation of cinnamaldehyde, the as-formed Cu nanowires show different catalytic performance in comparison with the unsupported Cu nanoparticles.

A self-supported CuO/Cu nanowire electrode (CuO/CuNWE), which was prepared by annealing Cu nanowires to form a porous Cu nanowire electrode (CuNWE) and then anodizing the as-prepared CuNWE in alkaline medium to generate Cu(OH)₂ nanowires followed by calcination, was employed for chemical oxygen demand (COD) determination using cyclic voltammetry (CV). The structure and electrochemical behavior of the CuO/CuNWE were investigated by scanning electron microscopy, X-ray diffraction, and CV. The results indicated that the as-synthesized CuO/CuNWE, in which CuO nanowires with a length of several micrometers and a diameter of 100 to 300 nm could be found, was stable in alkaline medium and more electrocatalytically active for oxidizing a wide range of organic compounds in comparison with the CuNWE. Under optimized alkaline concentration and scan rate, the CuO/CuNWE exhibited a good performance for COD measurement, with a linear range of 5 to 1153 mg L⁻¹, a sensitivity of 2.46× 10⁻² mA /(mg L⁻¹), and a detection limit of about 2.3 mg L⁻¹. In addition, an excellent correlation was observed in COD values obtained by our method and the classic dichromate method (r = 0.9995, p < 0.01, n = 11). Finally, our method was successfully used to measure the COD values in real water samples, showing great potential for practical application in water pollution control.

The outstanding catalytic properties of single-atom catalysts (SACs) stem from the maximum atom utilization and unique quantum size effects, leading to ever-increasing research interest in SACs in recent years. Ru-based SACs, which have shown excellent catalytic activity and selectivity, have been brought to the frontier of the research field due to their lower cost compared with other noble catalysts. The synthetic approaches for preparing Ru SACs are rather diverse in the open literature, covering a wide range of applications. In this review paper, we attempt to disclose the synthetic approaches for Ru-based SACs developed in the most recent years, such as defect engineering, coordination design, ion exchange, the dipping method, and electrochemical deposition etc., and discuss their representative applications in both electrochemical and organic reaction fields, with typical application examples given of: Li–CO₂ batteries, N₂ reduction, water splitting and oxidation of benzyl alcohols. The mechanisms behind their enhanced catalytic performance are discussed and their structure–property relationships are revealed in this review. Finally, future prospects and remaining unsolved issues with Ru SACs are also discussed so that a roadmap for the further development of Ru SACs is established.

While high-aspect-ratio metal nanowires are essential for producing nanowire-based electrodes of good performance used in electronics and electrocatalysis, the synthesis of millimeter-long Cu nanowires remains a challenge. This work demonstrates an oleylamine-mediated hydrothermal method for synthesis of Cu nanowires with an average diameter of ~80 nm and a length up to several millimeters. An investigation on the role of oleylamine in nanowire formation by mass spectroscopy, small angle X-ray diffraction and transmission electron microscopy reveals that oleylamine serves as a mild reducing agent for slow reduction of Cu(II) to Cu, a complexing agent to form Cu(II)-oleylamine complex for guiding the nanowire growth, as well as a surfactant to generate lamellar phase structure for the formation of nanowire bundles. The growth mechanism of these millimeter-long Cu nanowire bundles is proposed based on the experimental observations. Electrochemical measurements by linear sweep voltammetry indicate that the self-supported nanowire electrode prepared from as-formed Cu nanowire bundles shows high catalytic activity for electroreduction of nitrate in water.