In situ fast self-assembled preparation of dandelion-like Cu(OH)2@Cu3(HHTP)2 with core-shell heterostructure arrays for electrochemical sensing of formaldehyde in food samples

Formaldehyde is known to harm the respiratory, nervous, and digestive systems of people. In this paper, a novel dandelion-like electrocatalyst with core-shell heterostructure arrays were fast self-assembled prepared in situ using copper foam (CF) as support substrate and 2,3,6,7,10,11 hexahydroxy-triphenyl (HHTP) as ligand (Cu(OH)2@Cu3(HHTP)2/CF) by a simple two-step hydrothermal reaction. The 1D Cu(OH)2 nanorods "core" and the 2D π-conjugated conducting metal-organic frameworks (Cu3(HHTP)2cMOF) "shell" with remote delocalized electrons give the dandelion-like heterogeneous catalysts excellent electrochemical activity such as a large specific surface area, high conductivity and a fast electron transfer rate. The Cu(OH)2@Cu3(HHTP)2/CF exhibited excellent electrocatalytic performance for formaldehyde under alkaline conditions with a linear range of 0.2 μmol/L - 125 μmol/L and 125 μmol/L - 8 mmol/L, a detection limit as low as 15.9 nmol/L (S/N = 3), as well as good accuracy, consistency, and durability, and it effectively identified FA in food.

Cu(OH)2 supported on Fe(OH)3 as a synergistic and highly efficient system for the dehydrogenation of ammonia-borane

Herein, we first describe the physical mixture of Cu(OH)₂/Fe(OH)₃ as a composite catalyst precursor for the dehydrogenation of ammonia borane (AB) in methanol. During the initial period of catalytic reaction, Cu nanoparticles were formed in-situ. The catalytic activity of Cu nanoparticles can be significantly enhanced with the assistance of Fe species and OH^-. A maximum turnover frequency (TOF) of 50.3 mol_H2 mol_{total metal}^-1 min^-1 (135.6 mol_H2 mol_Cu^-1 min^-1) was achieved at ambient temperature, which is superior to those of previously reported Fe or Cu based systems.

Gravity-driven transport of three engineered nanomaterials in unsaturated soils and their effects on soil pH and nutrient release

The gravity-driven transport of TiO2, CeO2, and Cu(OH)2 engineered nanomaterials (ENMs) and their effects on soil pH and nutrient release were measured in three unsaturated soils. ENM transport was found to be highly limited in natural soils collected from farmland and grasslands, with the majority of particles being retained in the upper 0-3 cm of the soil profile, while greater transport depth was seen in a commercial potting soil. Physical straining appeared to be the primary mechanism of retention in natural soils as ENMs immediately formed micron-scale aggregates, which was exacerbated by coating particles with Suwannee River natural organic matter (NOM) which promote steric hindrance. Small changes in soil pH were observed in natural soils contaminated with ENMs that were largely independent of ENM type and concentration, but differed from controls. These changes may have been due to enhanced release of naturally present pH-altering ions (Mg(2+), H(+)) in the soil via substitution processes. These results suggest ENMs introduced into soil will likely be highly retained near the source zone.

Understanding the mechanism of ultrasound on the synthesis of cellulose/Cu(OH)2/CuO hybrids

Understanding the mechanism of ultrasound from metal hydroxide to oxides via an ultrasound irradiation method is of great importance for broadening and improving their synthesis and industrial applications. The purpose of this article was to explore the mechanism of ultrasound on the synthesis of cellulose/Cu(OH)2/CuO hybrids. The influences of various reaction parameters including the volume of H2O2, heating method, pulse mode of ultrasound irradiation, sonication time, and power density on the cellulose/Cu(OH)2/CuO hybrids were investigated in detail by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectra (EDS), thermogravimetric analysis (TGA), and derivative thermogravimetry (DTG). The experimental results indicated that all the parameters have effects on the cellulose/Cu(OH)2/CuO hybrids, power density had an effect on the phase transformation of Cu(OH)2 to CuO, and the addition of H2O2 played an important role in the shape of cellulose hybrids, which provided an indirect evidence on the H2O2-induced oxidation route for the transformation process from Cu(OH)2 to CuO during the ultrasound irradiation process. These results maybe direct the synthesis and potential applications of cellulose hybrids in the near future.