Sodium borohydride hydrolysis catalyzed by composite nanomaterials has long been proposed as a viable possibility for hydrogen generation, but it required either expensive noble metals or sophisticated composites. Herein, the catalysis of NaBH 4 hydrolysis is studied with single earth-abundant Fe, Co, Ni, and Cu nanoparticles supported by a metal organic framework (MOF), ZIF-8. It appears that CoNPs@ZIF-8 is the most efficient and selective catalyst in this series. The turnover frequency (TOF) related to the total atoms number within the cobalt nanoparticles reaches 14000 mL H2 min À 1 g Co À 1 at 30°C, and the TOF(s) related to the number of surface atoms of the cobalt nanoparticles 19400 mL H2 min À 1 g Co À 1 at 30°C. Kinetic studies including a high kinetic isotope effect disclosed using D 2 O (k H /k D = 6.85) and the favorable effect of NaOH lead to the suggestion of an oxidative addition of a OÀ H bond of water in the rate-determining step.

Tungsten nanoparticles have been synthesized by the sonoelectrochemical method. The electrolyte contained the tri-sodium citrate, sodium tungstate, ferrous sulphate, and citric acid. A platinum slice was used as the anode and a titanium-alloy horn as the cathode. Twenty kilohertz ultrasound generated by an ultrasound generator was connected to the titanium-alloy horn as an amplitude converter. Due to the electrochemical reaction and the cavitation effect of the ultrasound, the iron-tungsten aggregates at the cathode were dispersed into the electrolyte and iron atoms were dissolved in the acidic environment. In this way, body-center-cubic (bcc) tungsten nanoparticles have been obtained by controlling the density of the electric current, the ultrasound pulse period and amplitude. Their morphology, structure, and chemical components have been characterized using transmission electron microscope (TEM) and X-ray photoelectron spectrometer (XPS).

Abstract:The essential oil obtained by hydrodistillation from Alpinia kwangsiensis rhizomes was investigated by GC-MS. A total of 31 components representing 92.45% of the oil were identified and the main compounds in the oil were found to be camphor (17.59%), eucalyptol (15.16%), β-pinene (11.15%) and α-pinene (10.50%). These four compounds were subsequently isolated and the essential oil and four isolated compounds exhibited potent insecticidal activity against Lasioderma serricorne adults. During the assay, it was shown that the essential oil exhibited both potential contact (LD 50 = of 24.59 µg/adult) and fumigant (LC 50 = of 9.91 mg/L air) toxicity against Lasioderma serricorne. The study revealed that the insecticidal activity of the essential oil can be attributed to the synergistic effects of its diverse major components, which indicates that oil of Alpinia kwangsiensis and its isolated compounds have potential to be developed into natural insecticides to control insects in stored grains and traditional Chinese medicinal materials.

The development of well-defined atomically precise heteronuclear nanoclusters passivated by protecting ligands is presently a booming area, owing to the fact that doping well-known homonuclear nanostructures allows fine-tuning of their properties. Here, we explore by means of density functional theory calculations the possibility of doping the central gold atom in the classical [Au13(dppe)5Cl2]3+cluster (1) by Os. Although both [Au13(dppe)5Cl2]3+ and [Os@Au12(dppe)5Cl2] have the same total number of electrons, we show that they are not isoelectronic within the formalism of the superatom model, being respectively an 8- and an 18-electron species. It results that they exhibit similar structures but present significantly different optical behaviors (ultraviolet/visible and circular dichroism). Similar results are obtained for the Ru and Fe relatives. Emission properties indicate some redshift of the T1→S1 decay with respect to [Au13(dppe)5Cl2]3+, involving an equatorial distortion of the Au12Cl2 core in the T1 state, rather than the axial distortion afforded by 1. The sizable highest occupied molecular orbital–lowest unoccupied molecular orbital gaps found for the three doped species suggest that further experimental exploration of different stable doped species derived from the ligand-protected Au12Cl2 core should be encouraged.

Abstract:In order to find and develop new botanical pesticides against tobacco storage pests, bioactivity screening was performed. The essential oil obtained from the aerial parts of Liriope muscari was investigated by GC/MS and GC/FID. A total of 14 components representing 96.12% of the oil were identified and the main compounds in the oil were found to be methyl eugenol (42.15%) and safrole (17.15%), followed by myristicin (14.18%) and 3,5-dimethoxytoluene (10.60%). After screening, the essential oil exhibit potential insecticidal activity. In the progress of assay, it showed that the essential oil exhibited potent contact toxicity against Tribolium castaneum, Lasioderma serricorne and Liposcelis bostrychophila adults, with LD50 values of 13.36, 11.28 µg/adult and 21.37 µg/cm 2 , respectively. The essential oil also exhibited strong repellency against the three stored product insects. At the same concentrations, the essential oil was more repellent to T. castaneum than to L. serricorne adults. The results indicate that the essential oil of Liriope muscari has potential to be developed into a natural insecticide or repellent for controlling insects in stored tobacco and traditional Chinese medicinal materials.