Efficient photoelectrocatalytic degradation of azo-dyes over polypyrrole/titanium oxide/reduced graphene oxide electrodes under visible light: Performance evaluation and mechanism insights.

Herein, polypyrrole/titanium oxide/reduced graphene oxide (PTi/r-GO) electrodes were prepared and successfully applied for the photoelectrocatalytic (PEC) degradation of methyl orange (MO) under visible light. Polypyrrole-TiO2 composites rich in p-n heterojunctions were first prepared, then modified with r-GO to improve the electrical conductivity and facilitate charge separation under visible light irradiation. The obtained PTi/r-GO composites were then deposited onto a titanium mesh, which served as the working electrode in PEC experiments. A MO removal efficiency of 93% was achieved in 50 min using PTi/r-GO electrode under PEC conditions (Xe lamp, λ > 420 nm, bias of 0.6 V, 0.1 M Na2SO4 electrolyte), which was far higher than MO removal efficiencies under electrocatalytic oxidation (22%) or photocatalytic oxidation (47%) conditions. This confirmed that excellent activity of the PTi/r-GO electrode under PEC conditions was due to a combination of electrochemical and photocatalytic oxidation processes (involving •OH and •O2- generation). Further, PTi/r-GO was very stable under the applied PEC conditions, with the MO removal efficiency remaining >90% after five cycles. PEC degradation pathways for MO on PTi/r-GO were explored, with a number of key intermediates in the MO mineralization process identified. Results demonstrate that PEC electrodes combining p-type polypyrrole, n-type TiO2 and rGO are very effective in the treatment of hazardous organic compounds in wastewater.

Combining bioactivity and affinity to design of positive allosteric modulators of the metabotropic glutamate receptor using 3D-QSAR.

Communicated by Ramaswamy H. Sarma.

The feasibility and application of PPy in cathodic polarization antifouling.

Cathodic polarization antifouling deserves attention because of its environmentally friendly nature and good sustainability. It has been proven that cathodic voltages applied on metal substrates exhibit outstanding antifouling effects. However, most metals immersed in marine environment are protected by insulated anticorrosive coatings, restricting the cathodic polarization applied on metals. This study developed a conducting polypyrrole (PPy)/acrylic resin coating (σ = 0.18 Scm-1), which can be applied in cathodic polarization antifouling. The good stability and electro-activity of PPy in the negative polarity zone in alkalescent NaCl solution were verified by linear sweep voltammetry (LSV), chronoamperometry (CA), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), demonstrating the feasibility of PPy as cathodic polarization material. Furthermore, the antifouling effects of PPy/acrylicresin coating on 24-h old Escherichia coli bacteria (E. coli) which formed on PPy/acrylic resin-coated plastic plate were measured under different cathodic potentials and treatment time, characterized by fluorescent microscope. The results suggest that at cathodic potential around -0.5 V (vs. saturated calomel electrode (SCE)), there was little trace of attached bacteria on the substrate after 20 min of treatment. PPy/acrylicresin-coated substrates were also subjected to repeated cycles of biofilm formation and electrochemical removal, where high removal efficiencies were maintained throughout the total polarization process. Under these conditions, the generation of hydrogen peroxide is believed to be responsible for the antifouling effects because of causing oxidative damage to cells, suggesting the potential of the proposed technology for application on insulated surfaces in various industrial settings.

Patterned, highly stretchable and conductive nanofibrous PANI/PVDF strain sensors based on electrospinning and in situ polymerization.

A facile fabrication strategy via electrospinning and followed by in situ polymerization to fabricate a patterned, highly stretchable, and conductive polyaniline/poly(vinylidene fluoride) (PANI/PVDF) nanofibrous membrane is reported. Owing to the patterned structure, the nanofibrous PANI/PVDF strain sensor can detect a strain up to 110%, for comparison, which is 2.6 times higher than the common nonwoven PANI/PVDF mat and much larger than the previously reported values (usually less than 15%). Meanwhile, the conductivity of the patterned strain sensor shows a linear response to the applied strain in a wide range from 0% to about 85%. Additionally, the patterned PANI/PVDF strain sensor can completely recover to its original electrical and mechanical values within a strain range of more than 22%, and exhibits good durability over 10,000 folding-unfolding tests. Furthermore, the strain sensor also can be used to detect finger motion. The results demonstrate promising application of the patterned nanofibrous membrane in flexible electronic fields.

{N-[1-(1H-Benzimidazol-2-yl)ethyl-idene-κN]-3-(1H-imidazol-1-yl)propan-1-amine-κN}dibromidomercury(II).

In the title compound, [HgBr(2)(C(15)H(17)N(5))], the Hg(II) ion is tetra-hedrally coordinated by two N atoms of the N-[1-(1H-benzimidazol-2-yl)ethyl-idene-κN]-3-(1H-imidazol-1-yl)propan-1-amine ligand, and two bromide anions. Inter-molecular benzimidazole-imidazole N-H⋯N hydrogen bonds link the mol-ecules into helical chains along the b-axis direction and C-H⋯Br hydrogen bonds link these chains into layers parallel to the bc plane.

[(5-Bromo-1H-indol-3-yl)meth-yl]dimethyl-aza-nium nitrate.

In the title compound, C(11)H(14)BrN(2) (+)·NO(3) (-), inter-molecular N-H⋯O and N-H⋯N hydrogen bonds link the proton-ated 5-bromo-gramine cation and the nitrate anions. Further N-H⋯O hydrogen bonds link the cation-anion pairs into a chain running parallel to [100]. C-H⋯O hydrogen bonds link the chains, forming a layer parallel to (001).