Chuanqiang Zhou

Dilute Anionic Surfactant Solution Route to Polyaniline Rectangular Sub-microtubes as a Novel Nanostructure

A facile and low-cost approach has been developed for tailoring polyaniline rectangular sub-microtubes as a novel nanostructure of a conducting polymer in dilute sodium dodecyl sulfate (SDS) solution by the oxidation polymerization of aniline at room temperature. It was found that the size and uniformity of polyaniline rectangular sub-microtubes could be appropriately adjusted by tuning the concentration of aniline and the molar ratio of oxidant to aniline, respectively. The morphological evolution of rectangular sub-microtubes under different reaction times has been followed, and a possible formation mechanism has also been discussed in this report. The directing role of other anionic surfactants with -SO3(-) as the hydrophilic group for constructing polyaniline rectangular sub-microtubes has been investigated in detail.

Mesoporous Hybrid Shells of Carbonized Polyaniline/Mn2O3 as Non-Precious Efficient Oxygen Reduction Reaction Catalyst.

Mesoporous hybrid shells of carbonized polyaniline (CPANI)/Mn2O3 with well-controlled diameter and high surface area have been synthesized through surface protected calcination processes. Originating from polystyrene template, PANI, MnO2, and SiO2 were sequentially loaded, followed by template removal and calcination, resulting in the desired CPANI/Mn2O3 hybrid shells. The introduction of SiO2 shell was established to play the determining role in maintaining the configuration during calcination process under high temperature. The CPANI/Mn2O3 hybrid shells showed outstanding electrocatalytic activity toward oxygen reduction reaction (ORR), with the onset potential at +0.974 V (versus RHE), the specific current at 60.8 mA/mg, and an overall quasi 4-electron transfer, which are comparable to those of the benchmark Pt/C. The remarkable ORR performance was attributed to the high specific surface area, the surface oxidation state of Mn, and composition-codependent behavior.

Dilute cationic surfactant-assisted synthesis of polyaniline nanotubes and application as reactive support for various noble metal nanocatalysts

Well-defined and individual polyaniline (PANI) nanotubes have been synthesized by the oxidative polymerization of aniline in dilute solution in the presence of low-concentration cationic surfactant cetyltrimethylammonium bromide (CTAB). The role of the surfactant in the formation of the PANI nanostructures was discussed by changing its concentration in the reaction system, and the polymerization processes of low-concentration aniline in the dilute CTAB medium were deduced to explain the formation mechanism of the PANI nanotubes. Furthermore, noble metal (Au, Ag, Pt or Pd) nanoparticles that were supported on the as-synthesized PANI nanotubes have been achieved by utilizing the reactivity of PANI towards noble metal ions. Control over the size of noble metal nanoparticles, typical Au nanoparticles, that were uniformly supported on the surfaces of the PANI nanotubes has been realized by introducing a functional doping acid as the linkage. In addition, PANI nanotube/Au nanoparticle composites were found to serve as effective catalysts to activate the reduction of 4-nitrophenol (4NP) in the presence of NaBH4, and the size effects of the catalyst on the catalytic activity were also investigated.

Polyaniline Fan-Like Architectures of Rectangular Sub-Microtubes Synthesized in Dilute Inorganic Acid Solution

Rectangular-tube-based fan-like polyaniline has been readily fabricated by the oxidation polymerization of low-concentration aniline in dilute HCl aqueous solution for the first time. Different from the conventional polymerization that proceeds in concentrated acidic solution (to produce nanofibers), this synthesis was conducted in dilute inorganic acid solution at room temperature and created polyaniline hierarchical fan-like architectures. The morphological evolution of the product has been followed with respect to the reaction time, based on which conceivable interpretations of the formation of rectangular tubes and their assembly into fan-like architectures are given. Other inorganic acids (HNO(3) , H(2) SO(4) , and H(3) PO(4) ) with low concentrations have been used to replace HCl in the reaction system to validate the adaptability of this approach in this report.

A facile strategy to colloidal crystals by drying condensed suspension droplets.

Drying condensed colloid suspension droplet on a horizontal glass substrate has been developed as a simple strategy to fabricate highly-ordered colloidal crystals. A uniform film obtained at above room temperature possessed a face-center-cubic (fcc) crystalline structure and excellent photonic properties. It was found that raising the drying temperature has resulted in a reduction in the lattice spacing of fcc colloidal crystals. The formation reason of uniform fcc colloidal crystals was directly related to the high drying temperature and the large colloid concentration. A ring-shaped stain generated by drying at room temperature has exhibited other highly-ordered microstructures with colloidal crystals, such as body center cubic (bcc) structure.

Removal of Pb(II) and Zn(II) from Aqueous Solutions by Raw Crab Shell: A Comparative Study.

Removals of Pb(II) and Zn(II) ions from water using crab (Clistocoeloma sinensis) shell particles as biosorbent have been compared in this study. Uptake equilibriums for two ions well described by Langmuir isotherm revealed that crab shell possessed higher uptake capacity for Pb(II) (709 mg/g) than that for Zn(II) (117 mg/g). Kinetics data for the uptake of the two metals were successfully modeled using the pseudo-second-order model, where the initial uptake rate of Pb(II) was much faster than that of Zn(II). Dubinin-Radushkevick modeling and thermodynamic parameters hinted at different uptake mechanisms of Pb(II) and Zn(II) removal by crab shell, attested by FTIR, XRD, FESEM analysis. Pb(II) ion was removed mainly through the chemical reaction, while the uptake of Zn(II) ion onto crab shell was attributed to the chelation and coordination interactions. The polluted river water and laboratory wastewater both satisfied the standards for drinking and irrigation/fishery water, respectively, after being treated with crab shell particles.

Controlled synthesis of tower-like aniline oligomers with excellent adsorption properties

A nanoplate-based tower-like hierarchical architecture of aniline oligomers has been fabricated via the oxidation polymerization of aniline in NaOH aqueous solution at 35 °C, with ammonium peroxydisulfate as an oxidant. Experimental results indicated that the concentrations of NaOH and aniline, and temperature played important roles in the formation or the uniformity of such oligomer micro-towers. The offspring obtained at different reaction stages has been characterized by FESEM, FTIR and UV-vis techniques to gain insight into the morphological evolvement and chemical structure development of the tower-like product. Based on the results of these characterization techniques, the possible formation mechanism for the oligomer microtower was proposed. In addition, the adsorption properties of the aniline oligomer microtowers toward heavy metal ions (Cu(II) et al.) in water, as well as the sorption isotherms and kinetics were investigated carefully.

Ethanol-guided synthesis of (flower-on-leaf)-like aniline oligomers with excellent adsorption properties

A novel oligoaniline with hierarchical flower-on-leaf microstructures has been fabricated via the oxidation of aniline in EtOH/water (3 : 7, v/v) mixtures. The as-prepared oligoaniline was characterized using the UV-vis, FTIR, 1H NMR and MALDI-TOF MS techniques for analyzing the chemical structures. A possible formation mechanism has been proposed to interpret the growth of such hierarchical microstructures, and several inter-molecular interactions were suggested to drive the supermolecular assembly. The effect of the ethanol content in the medium on the morphology of the product was discussed, and the functions of the ethanol in the synthesis were explored. Besides, the adsorption properties of the as-prepared product toward organic dyes (crystal violet etc.) in water, as well as the sorption isotherms and kinetics, have been investigated carefully. The realizable sorption capacity for crystal violet was found to be 181 mg g−1 which was higher than those of most of the sorbent.

Controllable Supramolecular Chiral Twisted Nanoribbons from Achiral Conjugated Oligoaniline Derivatives

The fabrication of supramolecular chiral nanostructures from achiral materials without the need of pre-existing chirality is a major challenge associated with the origin of life. Herein, supramolecular chiral twisted nanoribbons of achiral oligoaniline derivatives were prepared via simply performing the chemical oxidation of aniline in an alcohol/water mixed solvent. In particular, the supramolecular chirality of the twisted nanoribbons could be controlled by facilely tuning the alcohol content in the mixed solvent. A tetra-aniline derivative C24H20O3N4 was attested to be the major component of the obtained nanoribbons. The main driving forces for the assembly of the oligoaniline derivative into twisted nanoribbons might be the π-π stacking and hydrogen bonding interactions among the chains which could be modulated by the alcohol content in the mixed solvent. The single-handed twisted nanoribbons could be used to separate chiral phenylalanine from a racemic mixture. Thus, it is highly anticipated that the supramolecular chirality endows π-conjugated molecules with potential application in chiral recognition.