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A new type of nanoporous carbon (NPC) was synthesized using dandelion pappus as a cost-effective carbon source through chemical activation with phosphoric acid. Notably, NPC is first considered to be used as an enhanced electrode material for the analysis of tryptophan (Trp). The high electrical conductivity of nanoporous carbon modified electrode (NPC/GCE) was better demonstrated by cyclic voltammetry using the ferricyanide system as a probe. Furthermore, the NPC/GCE exhibited an excellent electrocatalytic activity toward Trp oxidation with a decreased overpotential and improved current response, mainly due to the porous structure and large specific surface of nanoporous carbon. The electrocatalytic oxidation mechanism of Trp at the modified electrode was also investigated by cyclic voltammetry. The amperometric response of NPC-based sensor is linear in the 1 μM to 103 μM concentration range and the sensitivity is 171.43 μA mM −1  cm −2 . The proposed sensor was also successfully applied to the determination of Trp in real samples, and the satisfactory recoveries were obtained. [ABSTRACT FROM AUTHOR]

The 1 × 1 magnesium octahedral molecular sieve (Mg-OMS-7), utilizing as cathode material in aqueous rechargeable magnesium ions batteries, is synthesized by a simple one-step hydrothermal method. Meanwhile, by changing the concentrations of H 2 SO 4 , the Mg-OMS-7 materials with controllable size and shape are obtained. To check the structure and morphology, the host materials are measured by X-ray power diffraction, scanning, transmission and high-resolution transmission electron microscopy. The electrochemical reaction mechanism is examined by cyclic voltammetry and X-ray photoelectron spectroscopy. The Mg-OMS-7 changes the morphology from micro-rugby to nano-club by controlling the concentrations of H 2 SO 4 . The nano-club Mg-OMS-7 which obtained by the 1.6 mol dm − 3 H 2 SO 4 owns a more uniformly distribution and smaller size, which provides the shorter route for magnesium ions insert/deinsert into/from the lattice of host material and exhibits the better rate ability and cycle performance. The initial discharge capacity of this electrode can obtain 283.1 mAh g − 1 at the current density of 10 mA g − 1 in the 0.2 mol dm − 3 Mg(NO 3 ) 2 aqueous electrolyte and the specific capacity retention rate is 94.1% after cycling 200 cycles at 100 mA g − 1 in the 0.5 mol dm − 3 Mg(NO 3 ) 2 electrolyte. [ABSTRACT FROM AUTHOR]

Abstract: Carbon fiber cloth supported micro- and nano-structured Co electrode is prepared by a facile and fast square-wave electrodeposition method. The electrode is characterized by scanning electron microscope and X-ray diffractometer. Its electrocatalytic performance for hydrazine oxidation in alkaline media is investigated by means of cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy. Co is uniformly deposited on the carbon fiber surface and presents as nano-sheets and micro-particles intersected mutually. The nano-sheets have a thickness of around 250nm and the size of the micro-particles is up to around 10μm. Hydrazine electrooxidation on the electrode occurs via both direct and indirect pathways. The activation energy of the direct electrooxidation of hydrazine is 16.6kJmol−1 which is higher than that of the electrooxidation of hydrogen in the indirect pathway (9.9kJmol−1). [Copyright &y& Elsevier]

Abstract: The electrochemical behavior of the aluminum current collector with a fresh surface (the scratched aluminum foil) in three kinds of Grignard reagents/THF electrolytic solutions has been studied by cyclic voltammetry (CV), X-ray photoelectron spectroscopy (XPS) analysis methods. The experimental results show that the passivating film on aluminum foils after five cycles of CV tests is mainly composed of Al2O3. The pitting potentials of scratched aluminum foils in three kinds of Grignard reagents/THF electrolytic solutions increase in the order of EtMgCl/THF

Abstract: Nanostructured CuO with diverse morphology was directly grown on copper foam. Their supercapacitance performance was investigated and correlated with the morphology. CuO nanowires, nanosheets, and flower-like nanostructures were formed on copper foam which acts as both the substrate of CuO formation and the current collector of the electrode. Their morphology was examined by scanning and transmission electron microscopy and their phase structure was analyzed by X-ray diffraction spectroscopy. The supercapacitance of the nanostructured CuO on copper foam was investigated by cyclic voltammetry, galvanostatic charge/discharge measurements and electrochemical impedance spectroscopy. Results showed that the specific capacitance of the nanostructured CuO strongly depends on its morphology and dimension. CuO nanosheets exhibited higher specific capacitance than nanowires and flower-like nanostructure. The specific capacitance of the CuO nanosheets reached 212Fg−1 at a current density of 0.41mAmg−1 in 6.0moldm−3 KOH electrolyte. The capacitance loss is around 15% after 850 charge/discharge cycles at 0.41mAmg−1 and the majority of capacitance loss occurred in the initial 50 cycles (8.1%). [Copyright &y& Elsevier]

Rechargeable aqueous aluminum ion batteries (RAAB) have gained increasing attentions for large scale energy storage system due to their high safety, nontoxicity and low cost. However, lack of capable anode materials extremely hinders their potential application. As we all know, the anodic material of aluminum ion battery was limited, we report poly (3,4,9,10-perylentetracarboxylic diimide) (PPTCDI) under the different synthesis conditions as organic anode material for aqueous RAAB. The aluminum ions intercalation/deintercalation storage mechanism is affected by the different electrolyte concentrations. Upon their high capacity and cycling stability, our work would highlight potential application of conjugated polymer organic electrode materials for aqueous aluminum ion batteries. Unlabelled Image • The PPTCDI as anode in aqueous Al-ion battery was reported for the first time. • The Al-ion battery delivers excellent electrochemical cycling stability. • The aluminum ions intercalation/deintercalation storage mechanism is affected by the different concentrations of electrolyte. [ABSTRACT FROM AUTHOR]

In this work, one-pot hydrothermal method is used to prepare a novel electrode material of nanosheet-like Fe 2 O 3 in-situ grown on Ni foam. The performance of the as-prepared material toward H 2 O 2 oxidation is investigated systematically. The crossed nanosheet-like structure allows a full contact between the electrode surface and electrolyte which is highly beneficial to the sufficient use of H 2 O 2. The catalytic activity of Fe 2 O 3 grown on Ni foam(Fe 2 O 3 /Ni foam) electrode in alkaline medium for H 2 O 2 oxidation is researched by methods of cyclic voltammetry and chronoamperometry. According to the results of cyclic voltammetry in solutions with different H 2 O 2 concentrations, we proposes a possible reaction mechanism that the good ability of Fe3+ to break the oxygen-hydrogen bond in H 2 O 2 leads to the oxidation of H 2 O 2 on the electrode. Meanwhile, Ni foam also has a positive effect on the process of H 2 O 2 oxidation. In a solution of 4 mol L−1 NaOH and 0.4 mol L−1 H 2 O 2 , the current density of H 2 O 2 oxidation on the Fe 2 O 3 /Ni foam electrode is 800 mA cm−2 revealing a desirable catalytic activity toward H 2 O 2 oxidation. Besides, the activation energy of H 2 O 2 oxidation on the Fe 2 O 3 /Ni foam electrode is calculated to be 9.17 kJ mol−1 by studying the influence of temperature on the electrode performance. All the results show that the as-prepared electrode exhibits vast prospect in application. Image 1 • One-pot hydrothermal method was applied to prepare nanosheet-like Fe 2 O 3. • Fe 2 O 3 /Ni foam electrode exhibits good catalytic activity toward H 2 O 2 oxidation. • A possible mechanism of H 2 O 2 oxidation on Fe 2 O 3 /Ni foam electrode was proposed. [ABSTRACT FROM AUTHOR]