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A flexible nanocomposite of cobalt hexacyanoferrate (CoHCF) and commercial carbon cloth (CC) was prepared by facile electrodeposition of CoHCF on a flexible CC surface. As a kind of flexible integrated electrode without polymer binders, the flexible CC–CoHCF nanocomposites were directly used for nonenzymatic H2O2 sensing. Several techniques such as scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and electrochemistry were employed for the characterization of the electrode. It was found that CoHCF nanoparticles (about 100 nm) uniformly deposited on the CC surface. Electrochemical experiments demonstrated that the flexible CC–CoHCF nanocomposite electrode exhibited good electrocatalytic activity towards the oxidation of H2O2. Based on the amperometric experiments, the proposed nonenzymatic sensor showed a linear response to H2O2 detection in the range of 0.002–9.04 mM with a detection limit of 0.7 μM, which was superior to most of the previous results. Such a good result renders it a promising candidate for routine testing.

Three kinds of hierarchical porous carbon were successfully fabricated in the absence of any templates by carbonizing kenaf-nickel ion stems complex and subsequently etching nickel-doped carbon composites with hydrochloric acid. The pore size was easily controllable by changing the concentration of nickel ion solution. The unique porous structure of the products resulted in high specific surface area of 1480 m2 g−1. The creation of mesopores and macropores and construction of hierarchical pores not only improve the accessibility of the active centers, but also provide highways for reaction species, which result in an enhanced performance in a supercapacitor. The resulting porous carbon electrode materials showed improved specific capacitance of 327 F g−1 at a scan rate of 2 mV s−1 in 1.0 M H2SO4. Furthermore, the electrode showed a super-long cycle life with 95.6% retention of the initial specific capacitance after 5000 cycles at a current of 1 A g−1. This research demonstrated that the hierarchical porous carbon derived from kenaf stems was a good potential material in energy conversion and storage devices.