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Three-dimensional nitrogen-doped carbon network incorporated with nickel@nickel oxide core-shell nanoparticles composite (3D NC/Ni@NiO) has been facilely prepared, self-templated by the cross-linked polyacrylamide aerogel precursor containing NiCl2. Characterizations reveal that the Ni@NiO nanoparticles distribute homogeneously in the 3D nitrogen-doped carbon matrix and the composite is of hierarchical porous structure. When used as supercapacitor electrode in a three-electrode system, the 3D NC/Ni@NiO exhibits enhanced electrical conductivity and excellent electrochemical performance, presenting a high specific capacitance (389F g−1 at 5 mV s−1), good rate capability (276 F g−1 at 100 mV s−1) and outstanding cycling performance (with the capacitance retention of 70.2% after 5000 charge-discharge cycles). This is due to the synergistic effects of conductive metallic nickel, pseudocapacitive nickel oxide as well as in situ nitrogen doping of carbon network. Moreover, an asymmetric supercapacitor (ASC) was fabricated with NC/Ni@NiO as positive electrode and active carbon as negative electrode. The ASC device exhibits a maximum energy density of 19.4 W h kg−1 at a power density of 700 W kg−1 and shows good cycling stability (73.8% capacity retention after 3000 cycles), indicating that it has great promise for practical energy storage and conversion application.

We have developed a facile quaternarization strategy to an ultrathin lamellar g-C3N4 ionic liquid nanostructure (IL-CNNS) via a nucleophilic substitution between the tertiary amino groups in tri-s-triazine subunits and n-butyl bromide. After functionalization, the obtained IL-CNNS composite exhibits the enhanced conductivity, dispersibility and stability owing to the formation of IL structure. This composite has been characterized by several spectroscopic techniques (FT-IR, XRD, XPS, TGA and TEM). The IL-CNNS modified electrode displays the larger effective surface area and the faster electron transfer rate, hence resulting in the superior electrocatalytic activity toward 2,4-Dichlorophenol (2,4-DCP). Under the optimal conditions, the proposed 2,4-DCP sensor gives rise to the wide linear range from 0.02 to 160 μM with a low detection limit (6.21 nM, S/N = 3) by amperometric method. The developed sensor has been applied to detect 2,4-DCP in water samples with satisfactory recoveries and stability. This quaternarization strategy may open up a new avenue to fabricate the layered carbon nitride IL nanostructure for electrochemical sensing applications.

Fabricating high-performance and low-cost bifunctional electrocatalysts for both oxygen evolution and reduction reactions is vital for the practical application of renewable energy conversion. Herein, a hybrid of Co3O4/Co active species incorporated in N-doped porous carbon matrix, denoted as Co3O4/Co-NPC, has been prepared using a scalable and facile method involving the carbonization of alginate composite after a Co ion exchange with sustainable seaweed biomass. The 3D Co3O4/Co-NPC exhibits good bifunctional oxygen electrocatalytic performance in alkaline medium. The proposed catalyst gives the smaller onset potential (1.450 V vs. RHE) and overpotential (277 mV) at 10 mA cm−2 current density, indicating a superior oxygen evolution reaction activity to commercial IrO2 catalyst. It also performs the excellent oxygen reduction catalytic activity with larger onset potential (0.91 V vs. RHE), more positive half wave potential (0.806 V vs. RHE) and bigger diffusion-limiting current density (−5.86 mA cm−2 at 0.4 V). The Co3O4/Co-NPC hybrid experiences an almost ideal 4e process with better long-term stability and anti-methanol ability than commercial Pt/C catalyst in 0.1 M KOH. The prominent bifunctional activity of Co3O4/Co-NPC can be due to the synergistic effects of the well dispersed Co3O4/Co active species and N-doped porous carbon nanostructure.

Photo-responsive materials with adjustable self-assembly morphologies and tunable rheological properties have attracted widespread interests of researchers in recent years because of their potential applications in controlled release, microfluidics, sensors, and so forth. In this paper, a series of UV-sensitive anisotropic fluids were prepared by combining trans-ortho-methoxycinnamate (trans-OMCA, in its salts form) and cationic Gemini surfactant propanediyl-α, ω-bis (N-dodecyl-N, N-dimethylammonium bromide) (12-3-12·2Br−) based on the research of self-assembly behaviors of the mixed system. The photo-responsive behaviors of anisotropic fluid formed in 12-3-12·2Br−/trans-OMCA/H2O system including macroscopic phase transition, microstructure transformation, rheological property, molecular interaction and isomerization degree of trans-OMCA were investigated by various techniques including UV-vis spectrum, rheology measurement, 1H NMR and 2D NOESY spectrum, transmission electron microscopy (TEM), polarized optical microscopy (POM), and dynamic light scattering (DLS). It is proved that upon exposure to UV-light, ortho-methoxycinnamate (OMCA) undergoes a photo-isomerization from trans form to cis form, which results in geometry transitions of the 12-3-12·2Br−/OMCA aggregates accompanied by a continuous phase separation and combination macroscopically; both proportion and concentration of OMCA in anisotropic solution have great influences on the photo-responsive behaviors of the system including the durations of UV irradiation and isomerization degrees of OMCA at the phase transition points. The photo-responsiveness of this smart fluids and the quantitative analysis are expected to provide reference for academic research or practical application in the fields of biomedicine, soft matters, food engineering and sunscreen.

This study demonstrated a generic and simple approach to generate durable antibacterial ability on cellulose without using covalently bonding tethering groups that limit the structure design. CO2-philic silicone with quaternary ammonium salt (QAS) pendants was synthesized through hydrosilylation reaction of poly(methylhydrosiloxane) (PMHS) and 2-(dimethylamino)ethyl acrylate in the presence of platinum-based catalyst and subsequent quaternization with 1-bromohexane. The resultant QAS silicone was deposited onto cellulose by adsorption from supercritical CO2 (scCO2) to provide potent biocidal activities against Staphylococcus aureus and Escherichia coli. Presented data also showed that the antibacterial layer was very stable toward washing and UV irradiation owning to the low surface tension and relatively high bond energy of the backbone of silicone. This procedure is applicable to substrates of other shape and chemistry.