We have prepared a nanoporous Fe–C–N catalyst with promising ORR activity via a combined chemical precipitation and pyrolysis method. Cyanamide, Fe(NO3)3, and graphene oxide (GO) were used as the N, Fe, and C precursors, respectively. The synthesized Fe–C–N has a unique beanpod-shaped nanostructure with a specific surface area determined as 186 m2 g−1. Furthermore, a limiting current density of 6.1 mA cm−2 in phosphate buffer solution (PBS pH 7.0) was achieved, which is nearly twice that obtained with commercial Pt@C. The Fe–C–N catalyst was used as the cathode of a fuel cell (FC) to recover energy from organic fuels in neutral solution.

A polyaniline–graphene–TiO2 (PANI–GR–TiO2) hybrid has been successfully synthesized by coating graphene nanosheets (GR) on the surface of TiO2 and the subsequent chemical polymerization of aniline. The synthesized ternary PANI–GR–TiO2 was thoroughly studied by using scanning electron microscopy (SEM), Raman spectroscopy, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The PANI–GR–TiO2 hybrid displays promising oxygen evolution reaction (OER) activity for photoelectrocatalytic water oxidation. Moreover, the durability of the ternary hybrid was greatly improved due to the coating of PANI and GR on the surface of TiO2. Finally, a reasonable mechanism was proposed to understand the enhanced activity of the PANI–GR–TiO2 hybrid using UV-Vis absorption spectroscopy and photoluminescence (PL) emission spectroscopy. Our results clearly demonstrate that integrating GR and PANI with TiO2 through a simple route results in an efficient ternary photocatalyst with prominent OER performance for visible-light photoelectrocatalytic water oxidation.

Graphene-based materials have been widely used as electrode materials of supercapacitors. However, the intrinsic properties related to the capacitance of graphene-based materials essentially need to be clarified. In this work, we have prepared reduced graphene oxide (RGO) through a simple chemical reduction strategy by using hydrazine hydrate as the reducing reagent. The different reduction levels of graphene sheets were successfully realized by controlling the chemical reduction time, and the surface state and density of the functional group were precisely adjusted. We investigated the electrochemical performance of the as-prepared RGO electrode materials. A time dependence of the specific capacitance for the as-prepared RGO electrode was observed. Graphene oxide reduced by hydrazine hydrate at 95 °C for 60 min exhibited the highest weight specific capacitance. The RGO samples were systematically characterized with Fourier transform infrared (FTIR) spectra, X-ray photoelectron spectroscopy (XPS), and Raman measurements. We conclude that the oxygen-containing groups, electrical conductivity, density of defects, and carbon electronic state play substantial roles in deciding the specific capacitance of reduced graphene oxide.Keywords: capacitance; chemical reduction; graphene oxide; hydrazine hydrate;

Design and synthesis of three-dimensional (3D) structured carbon materials are crucial for achieving high-performance supercapacitors (SC) for energy storage. Here, we report the preparation of 3D architectured GN-CNT hybrid as SC electrodes. Controllable growth of carbon nanotubes on graphene sheets was realized through a facile one-pot pyrolysis strategy. The length of the carbon nanotubes could be rationally tuned by adjusting the amount of precursors. Correspondingly, the resulted GN-CNT hybrid showed adjustable electrochemical performance as an SC electrode. Importantly, the GN-CNT exhibited a high specific surface area of 903 m2 g–1 and maximum specific capacitance of 413 F g–1 as SC electrodes at a scan rate of 5 mV s–1 in 6 M KOH aqueous solution. This work paves a feasible pathway to prepare carbon electrode materials with favorable 3D architecture and high performance, for use in energy storage and conversion.Keywords: 3D architecture; carbon nanotube; controllable growth; graphene; one-pot strategy; supercapacitor;

We report the fabrication of novel CuO@Cu nanostructure with tuneable morphology and electrochemical properties. An H2O2 sensor with tuneable sensing features and promising electro-oxidation of MeOH at the CuO@Cu electrode are demonstrated. The constructed H2O2 sensor based on the optimized CuO@Cu electrode has a detection limit of 11 μM.

A polyaniline–graphene–TiO2 (PANI–GR–TiO2) hybrid has been successfully synthesized by coating graphene nanosheets (GR) on the surface of TiO2 and the subsequent chemical polymerization of aniline. The synthesized ternary PANI–GR–TiO2 was thoroughly studied by using scanning electron microscopy (SEM), Raman spectroscopy, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The PANI–GR–TiO2 hybrid displays promising oxygen evolution reaction (OER) activity for photoelectrocatalytic water oxidation. Moreover, the durability of the ternary hybrid was greatly improved due to the coating of PANI and GR on the surface of TiO2. Finally, a reasonable mechanism was proposed to understand the enhanced activity of the PANI–GR–TiO2 hybrid using UV-Vis absorption spectroscopy and photoluminescence (PL) emission spectroscopy. Our results clearly demonstrate that integrating GR and PANI with TiO2 through a simple route results in an efficient ternary photocatalyst with prominent OER performance for visible-light photoelectrocatalytic water oxidation.

We have prepared a nanoporous Fe–C–N catalyst with promising ORR activity via a combined chemical precipitation and pyrolysis method. Cyanamide, Fe(NO3)3, and graphene oxide (GO) were used as the N, Fe, and C precursors, respectively. The synthesized Fe–C–N has a unique beanpod-shaped nanostructure with a specific surface area determined as 186 m2 g−1. Furthermore, a limiting current density of 6.1 mA cm−2 in phosphate buffer solution (PBS pH 7.0) was achieved, which is nearly twice that obtained with commercial Pt@C. The Fe–C–N catalyst was used as the cathode of a fuel cell (FC) to recover energy from organic fuels in neutral solution.