Copper(II) and Nickel(II) Complexes Derived from Isostructural Bromo- and Fluoro-Containing Bis-Schiff Bases: Syntheses, Crystal Structures and Antimicrobial Activity.

A mononuclear copper(II) complex [CuLa] (1), and three mononuclear nickel(II) complexes [NiLa] (2), [NiLa]·CH3OH (2·CH3OH) and [NiLb] (3), where La and Lb are the dianionic form of N,N'-bis(4-bromosalicylidene)-1,2-cyclohexanediamine (H2La) and N,N'-bis(4-fluorosalicylidene)-1,2-cyclohexanediamine (H2Lb), respectively, were prepared and structurally characterized by spectroscopy method and elemental analyses. The detailed structures were determined by X-ray single crystal diffraction. All the copper and nickel complexes are mononuclear compounds. The metal ions in the complexes are in square planar coordination, with the two phenolate oxygens and two imine nitrogens of the Schiff base ligands. The biological effect of the four complexes were assayed on the bacteria strains Staphylococcus aureus, Escherichia coli and Candida albicans.

Green preparation of graphene oxide nanosheets as adsorbent.

As a basic building block of graphene-based materials, graphene oxide (GO) plays an important role in scientific research and industrial applications. At present, numerous methods have been employed to synthesize GO, there are still some issues that need to be solved, thus it is of importance to develop a green, safe and low-cost GO preparation method. Herein, a green, safe and fast method was designed to prepare GO, namely, graphite powder was firstly oxidized in a dilute sulfuric acid solution (H2SO4, 6 mol/L) with hydrogen peroxide (H2O2, 30 wt%) as oxidant, and then exfoliated to GO by ultrasonic treatment in water. In this process, H2O2 was the only oxidant, and no other oxidants were used, thus the explosive nature of GO preparation reaction in the conventional methods could be completely eliminated. This method has other advantages such as green, fast, low-cost and no Mn-based residues. The experimental results confirm that obtained GO with oxygen-containing groups has better adsorption property compared to the graphite powder. As adsorbent, GO can remove methylene blue (50 mg/L) and Cd2+ (56.2 mg/L) from water with removal capacity of 23.8 mg/g and 24.7 mg/g, respectively. It provides a green, fast and low-cost method to prepare GO for some applications such as adsorbent.

Facile preparation of Ti3C2Tx sheets by selectively etching in a H2SO4/H2O2 mixture.

MXenes and MXene-based composite materials have potential applications in a wide range of areas due to their unique physical and chemical characteristics. At present, it is still a major challenge to develop a simple, safe, and efficient route to prepare MXenes without using fluorinated etchants. Herein, we design a facile method to prepare Ti3C2Tx MXene sheets by selectively etching Ti3AlC2 powders in an aqueous diluted H2SO4 solution with H2O2 as an oxidant. In a system of H2SO4 and H2O2, an aqueous H2SO4 solution with a concentration of 6 mol/L is a strongly acidic medium with no volatility, and 30% H2O2 acts as a strong green oxidizer without harmful by-products. The experimental process is safe and convenient to conduct in a beaker under a water bath of 40°C. The etching process can be completed in 1 h under the air atmosphere conditions. The experimental results confirmed that the etched Ti3AlC2 powders can be successfully separated into Ti3C2Tx nanosheets under ultrasound treatment without using any intercalation agent. The relevant etching mechanism is may be attributed to the synergy effect of H2SO4 and H2O2, which triggers sequential selective etching of Al layers from the Ti3AlC2 phase. It may provide a new green way to prepare MXene-based materials without using toxic HF or HF-containing etchants.

3D Graphene Oxide Hydrogel Derived from Waste Toner as Adsorbent.

Waste toner powders are considered as hazardous materials to human and living things, and should be properly recycled by many effective ways due to their fine particle sizes and complex components. In this paper, waste toner powders were used as raw materials to successfully synthesize three dimensions (3D) graphene oxide (GO) hydrogel by means of a one-pot chemical transformation based on the improved Hummers' method. The obtained 3D GO hydrogel has porous structure and abundant oxygen-containing functional groups because of the inherent 3D solid structure of waste toner powder and the strong oxidation process of the improved Hummers' method. Interestingly, the as-prepared 3D GO hydrogel with excellent adsorptive property could quickly remove Pb(II) ions (100 mg/L, removal efficiency of 96% and removal capacity of 144 mg/g) and methylene blue (50 mg/L, removal efficiency of 97% and removal capacity of 48 mg/g) from water, respectively. The preparation process of 3D GO hydrogel was simple and easy to operate, and the output can be moderately mass produced, thus it would provide a new and effective disposal way for the recycling and reusing of waste toner.

Tin-sulfur based catalysts for acetylene hydrochlorination.

In the present work, tin-sulfur based catalysts were prepared using Na2SO3 and (CH3SO3)2Sn and were tested in acetylene hydrochlorination. Based on the analysis of experiments results, the acetylene conversion of (CH3SO3)2Sn/S@AC is still over 90%after a 50 h reaction, at the reaction conditions of T = 200 oC, VHCl/VC2H2 = 1.1:1.0 and C2H2-GSHV = 15 h-1. According to the results of X-ray photoelectron spectroscopy (XPS), HCl adsorption experiments, and acetylene temperature programmed desorption (C2H2-TPD), it is reasonable to conclude that the interaction between Sn and S not only can retard the oxidation of Sn2+ in catalysts but also strengthen the reactant adsorption capacity of tin-based catalysts. Furthermore, results obtained from nitrogen adsorption/desorption and XPS proved that the CH3SO3- can effectively decrease the coke deposition of (CH3SO3)2Sn/AC and thus prolong the lifetime of (CH3SO3)2Sn/AC.

Facile preparation of porous biomass charcoal from peanut shell as adsorbent.

Activated carbons derived from biomass have been proved to be one of the most promising adsorbents due to their abundance, low cost, reproducibility and environmental friendliness. In this study, a simple, facile and effective pyrolysis method was demonstrated to prepare hierarchical porous biomass charcoal by using peanut shells as precursor without chemical activation in an electric muffle furnace. The obtained products hold porous structure and abundant oxygen-containing functional groups, which were mainly due to in-built template of the structure of peanut shell and the preparation process without nitrogen protection, respectively. Interestingly, the obtained biomass charcoal sample with excellent adsorptive property quickly removed Pb2+ (100 mg/L) and methylene blue (50 mg/L) from water with removal efficiency of 96.5% and 97.1%, and removal capacity of 48 mg/g and 24 mg/g, respectively. The synthetic process was simple and economical, and it could be used as a beneficial reference in the recycling of biomass waste.

Photoelectrocatalytic Hydrogen Generation Enabled by CdS Passivated ZnCuInSe Quantum Dot-Sensitized TiO2 Decorated with Ag Nanoparticles.

Here we present the photoelectrocatalytic hydrogen generation properties of CdS passivated ZnCuInSe (ZCISe) quantum dots (QDs) supported by TiO2 nanowires decorated with Ag nanoparticles. In this configuration, Ag nanoparticles were sandwiched between the photo-electrons collector (TiO2) and photo-sensitizers (ZCISe), and acted as an electron relay speeding up the charge carrier transport. ZCISe and CdS enabled the optical absorption of the photoelectrode ranging from ultraviolet to near infrared region, which significantly enhanced the solar-to-chemical energy conversion efficiency. A photocurrent of 10.5 mA/cm² and a hydrogen production rate of about 52.9 µmol/h were achieved under simulated sunlight (1.5 AG).

Visible-light photocatalytic capability and the mechanism investigation of a novel PANI/Sn3O4 p-n heterostructure.

A novel polyaniline (PANI)/Sn3O4 heterojunction composed of PANI nanofibers and Sn3O4 nanosheets was fabricated by a facile physical milling technique. Modification of Sn3O4 with a PANI conductive polymer contributes to facilitating interfacial charge transfer efficiency, and thus, significantly enhances the visible-light Rhodamine B (RhB) photo-degradation. Results indicate that PANI/Sn3O4 heterostructures with 10 wt% PANI reached the maximum degradation efficiency (around 97%) for RhB within 5 h, which is 2.27 times higher than that of Sn3O4 alone. This improvement is due to the p-n heterostructure formation in PANI/Sn3O4. Moreover, the outcome of reactive species capturing experiments demonstrated that in PANI/Sn3O4, holes made the largest contribution to RhB degradation under visible light illumination, while hydroxyl radicals showed less significance under the same conditions. In addition, the photocatalytic mechanism was proposed based on evidence from the reactive species test and energy band structure analysis.

Multi-functional CuO nanowire/TiO2 nanotube arrays photoelectrode synthesis, characterization, photocatalysis and SERS applications.

Vertically aligned single crystalline CuO nanowire arrays (NWs) grown directly on TiO2 nanotube arrays (NTAs) supporting by Ti foil have been successfully fabricated using facile thermal oxidation of Cu nanocrystals in static air. CuO NWs growth behavior dependent on parent Cu nanocrystals sizes has been well investigated. Mass transport channel of Cu ions in horizontal and vertical for supporting CuO NWs diameter and length changes has been confirmed through a novel step-by-step surface diffusion process. CuO NWs, nano-mushrooms and nanosheets can be easily obtained by varying growth conditions. After photocatalytic synthesis of snow-like Ag nanocrystals upon CuO NWs/TiO2 NTAs, the hybrid photoelectrode exhibits superior catalytic property and detection sensitivity, which can clean themselves by photocatalytic degradation of RhB molecules adsorbed to the substrate under irradiation using surface enhanced Raman scattering (SERS) detection, a recycling can been achieved.