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A novel ultraviolet (UV)- and visible-light-active 3D graphene aerogels (3DGA)/Sb2WO6 hybrid photocatalyst was prepared by electrostatic self-assembly (ESSA) method. The photocatalytic activity of the 3DGA/Sb2WO6 hybrid was studied by monitoring the change in the concentration of methyl orange (MO) under UV-light and visible-light irradiation. The results demonstrated that the as-prepared hybrid exhibited significantly enhanced efficiency for the photodegradation of MO in comparison with pure Sb2WO6. This was ascribed to the efficient separation of the photogenerated electrons (e–) and holes (h+) with the aid of 3DGA as well as the generated reactive superoxide radical anions (O2•–). Moreover, the 3DGA/Sb2WO6 hybrid exhibited high recyclability, because the highly hydrophobic 3DGA in the hybrid was very advantageous to the separation of the hybrid photocatalyst from the MO solutions.

Hierarchical mesoporous Co3O4/C@MoS2 core-shell structured materials are synthesized via a two-step calcination and a solvothermal method using cobalt metal-organic frameworks (cobalt-MOFs, ZIF-67) and (NH4)2MoS4 as the precursors of Co3O4/C and MoS2, respectively, which is a new class of core-shell materials as supercapacitor electrode materials. The obtained Co3O4/C@MoS2 exhibits high specific capacitance (1076 F g−1 at 1 A g−1), rate capability (76.9% capacitance retention at 10 A g−1) and cyclic stability (64.5% capacitance retention after 5000 cycles at 10 A g−1). Moreover, the content of MoS2 greatly influences the electrochemical performances of the obtained core-shell materials. The results demonstrate that the as-synthesized ZIF-67 can be used as a promising candidate for designing Co3O4 based core-shell materials used in supercapacitors.

Sulfur-doped titanium dioxide (S-TiO2) was hydrothermally synthesized using thiourea as the sulfur source, and then it was successfully integrated to the three-dimensional graphene aerogels (3DGA). The obtained nanocomposites of S-TiO2 and 3DGA (S-TiO2-3DGA) were characterized by XRD, SEM, TEM, XPS and UV–vis diffuse reflectance spectroscopy. When the nanocomposites were applied for the photodegradation of methyl orange (MO), the photocatalytic activity of TiO2 was significantly improved by doping of S and integration with 3DGA, which might be due to the narrowed bandgap of S-TiO2 and the good conductive ability and 3D structure of 3DGA. More importantly, the hydrophobic property of 3DGA makes it easy to separate the S-TiO2-3DGA from the water phase, resulting in excellent recyclability and high stability of the photocatalyst.

We report the facile synthesis of N-doped carbon-graphene-manganese oxide (N/C-G-MnO) that can serve as precious metal-free electrocatalysts for oxygen reduction reaction (ORR). The N/C-G-MnO is synthesized via polymerization of m -phenylenediamine adsorbed on graphene using KMnO 4 as the oxidant, followed by pyrolyzation of the resulting N- and MnO 2 -containing poly( m -phenylenediamine). That is, poly( m -phenylenediamine) plays multi-roles in the synthesis of the ORR catalysts: (i) Serving as interlayer spacer to prevent graphene sheets from restacking during the thermal annealing, (ii) Function as the source of N-doped carbon (N/C) and MnO for the simultaneous doping of graphene. The N/C-G-MnO exhibits better ORR activity, long-term stability and methanol tolerance than those of the commercial Pt (5%)/C catalyst.

Sulfur and nitrogen codoped three-dimensional graphene-MnS (MnS/S,N-3DG) hybrids are facilely synthesized via a hydrothermal method followed by freeze-drying and pyrolysis treatment. The obtained MnS/S,N-3DG as an electrocatalyst for oxygen reduction reaction (ORR) shows excellent electrocatalytic performance. The codoped S and N as well as the introduced MnS significantly promote the electrocatalytic activity of graphene and efficiently catalyze the ORR process through a mixture of two-electron transfer pathway and four-electron transfer pathway (electron transfer number equals to 3.8 or 3.9), which is even better than the commercial Pt (5%)/C catalyst. Moreover, the developed MnS/S,N-3DG electrocatalyst possesses excellent long-term stability and methanol tolerance, and could be a promising cathode electrocatalyst in future energy conversion and storage systems.

Poly(aniline- co - m -aminophenol)(PANMA)/graphene/NiO nanocomposite was synthesized and applied as a supercapacitor electrode for the first time. Graphene/NiO nanocomposite was first synthesized via a hydrothermal synthesis method from Ni(NO 3 ) 2 ·6H 2 O, urea, and graphite oxide. NiO nanoparticles were distributed uniformly on both sides of the graphene. Then, PANMA was deposited in situ on the surface of the graphene/NiO nanocomposite via the copolymerization of aniline and m -aminophenol. The obtained nanocomposite has a similar porous morphology with that of PANMA. Experimental results indicate that the synergistic contributions from PANMA, graphene and NiO enable the composite electrode with substantially improved energy storage performance metrics. The nanocomposite shows a high specific capacitance of 562 F g −1 at a current density of 0.5 A g −1 , a good rate capability even at high current densities and a better long-term cycling stability.

Graphene–polyaniline–MnO 2 (G–P–Mn) hybrids were synthesized via a facile approach that includes the reduction of graphene oxide (GO) to graphene (G) by aniline and then followed by oil–water interfacial polymerization of aniline to polyaniline (PANI) using a binary oxidant of KMnO 4 and (NH 4 ) 2 S 2 O 8 . PANI was orderly nanofibered and MnO 2 -doped due to interfacial polymerization and the use of binary oxidant. The hybrids conclude electrical double layer capacitance of G and pseudo capacitance of PANI and MnO 2 , showing enhanced specific capacitance of 800.1 F g −1 at 0.4 A g −1 with good cycling stability.

ZnO and CuO co-decorated porous carbon spheres (PCS) were prepared via a simple hydrothermal method, denoted as ZnO-CuO/PCS. An electrochemical sensor based on the ZnO-CuO/PCS was fabricated for simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA). Three well-resolved anodic peaks along with greatly increased peak currents were obtained at the ZnO-CuO/PCS modified glassy carbon electrode (GCE) on the differential pulse voltammograms. The anodic peak separations at the ZnO-CuO/PCS/GCE were 204 mV between AA and DA and 132 mV between DA and UA. Notably, the analytical performances of the ZnO-CuO/PCS outperform those of ZnO/PCS and CuO/PCS, which can be attributed to the synergistic effect of the two metallic oxides, i.e., the formation of p-n heterojunctions between p-type CuO and n-type ZnO allows sensitive transduction into remarkable changes in the electrochemical signals. The ZnO-CuO/PCS/GCE also presented high anti-interference ability, storage stability and repeatability in the determination of AA, DA and UA. Finally, the practical applicability of the prepared sensor was successfully demonstrated by the simultaneous determination of AA, DA and UA in human urine samples.

A simple method to synthesize Zn 2+ doped poly(aniline- co - m -aminophenol) (PANMA), Zn-PANMA, for supercapacitors is reported. Capacitive behaviors of the copolymer based supercapacitor in 1 M H 2 SO 4 electrolyte were examined by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and galvanostatic charge/discharge. The morphological characteristics of Zn-PANMA and PANMA doped with Fe 3+ and Cu 2+ were investigated by field emission scanning microscopy (FESEM), explaining the different capacitive behaviors of these transition metal ions doped PANMA. A specific capacitance of Zn-PANMA as high as 631 F g −1 was achieved at a current density of 0.5 A g −1 , due to the enhancement of the electrochemical properties of the copolymer by Zn 2+ doping. Moreover, the specific capacitance still remained 71.7% after cycling for 800 times, exhibiting a good cycling performance and structure stability of Zn-PANMA.

A novel double-potential technique is applied for the electrodeposition of Pt nanoparticles (PtNPs) with controllable size on poly( m -phenylenediamine) (P m PD). The double-potential technique is comprised of the control of the electrodeposition time of PtNPs, followed by the electromodulation of PtNPs size. Oxidation of methanol on the resulting PtNPs/P m PD was investigated, indicating that PtNPs/P m PD exhibits excellent catalytic activity and satisfactory poisoning-tolerance toward methanol oxidation, which is due to the synergistic effect of PtNPs and P m PD. The results demonstrate that PtNPs/P m PD can be a promising electrode material used in the direct methanol fuel cell (DMFC).

An electrochemical immunosensing method was developed based on poly( m -aminophenol) (P m AP) immobilized goat anti-human IgG (anti-IgG). Glutaraldehyde (GA) was used as a coupling reagent, its two aldehyde groups reacted with the amino groups of P m AP electrodeposited on the expanded graphite (EG) surfaces and the amino groups of anti-IgG, respectively. In this immunoassay, human IgG was fixed as the target antigen, horseradish peroxidase (HRP)-conjugated goat anti-human IgG (HRP-anti-IgG) as the probing antibody and poly(methylene blue) (PMB) as the electron mediator. The oxidation peak current of PMBH (the reduction state of PMB) was proportional to the concentration of IgG in the range from 5 to 60 μg mL −1 , and the detection limit was 0.19 μg mL −1 (signal-to-noise ratio of 3). The proposed system reduced complexity and costs which are considered as the most wanted features in the point-of-care diagnostics application of clinical screening of multiple diseases.