Haisheng Tao

Carbon Nanocages as Supercapacitor Electrode Materials

Supercapacitor electrode materials: Carbon nanocages are conveniently produced by an in situ MgO template method and demonstrate high specific capacitance over a wide range of charging-discharging rates with high stability, superior to the most carbonaceous supercapacitor electrode materials to date. The large specific surface area, good mesoporosity, and regular structure are responsible for the excellent performance.

Facile Construction of Pt–Co/CNx Nanotube Electrocatalysts and Their Application to the Oxygen Reduction Reaction

A straight forward method for immobilizing Pt-Co alloyed nanoparticles onto nitrogen-doped CNx nanotubes is presented. The as-prepared electrocatalysts exhibit good performance for oxygen reduction reaction in acidic medium arising from the high-dispersion and alloying effect of the Pt-Co nanoparticles and the intrinsic catalytic capacity of the CNx nanotubes.

CNx nanofibers converted from polypyrrole nanowires as platinum support for methanol oxidation

A new kind of carbon nitride (CNx) nanofiber has been prepared by the calcination of polypyrrole nanowires at 800 °C. The product maintained a wire-like morphology during calcination, and the pyrrolic nitrogen in the polypyrrole nanowires gradually changed to pyridinic and graphitic nitrogen as annealing temperature increased. These CNx nanofibers, prepared at 800 °C, have a nitrogen concentration of about 10%. Pt nanoparticles with average size of ∼3 nm could therefore be easily immobilized onto the CNx nanofibers because of the inherent chemical activity arising from the nitrogen incorporation. The Pt/CNx composite catalyst thus obtained has a large electrochemically active area and gives good electrocatalytic performance for methanol oxidation, both in activity and stability, suggesting it has potential application in fuel cells.

CNx nanotubes as catalyst support to immobilize platinum nanoparticles for methanol oxidation

Pt nanoparticles with sizes of 3–9 nm were well dispersed on carbon nitride (CNx) nanotubes without needing pre-surface modification on the CNx nanotubes due to the inherent chemical activity. The products were characterized by transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. All the experimental results revealed that Pt nanoparticles were immobilized on the CNx nanotubes due to the N-participation in the connection of Pt species with the support. The electrocatalytic property of the as-prepared Pt/CNx catalyst in methanol oxidation was examined by cyclic voltammetry. The results reveal that the so-constructed Pt/CNx catalyst has obvious catalytic activity, suggesting potential applications in fuel cells.

Patterned growth and field-emission properties of AlN nanocones.

AlN is well known for its small (even negative) electron affinity, high stability, and superior thermal conductivity. Recently, various 1D AlN nanostructures such as nanotubes, nanowires, nanobelts and nanocones have been synthesized. Among them, AlN nanocone arrays exhibit good field emission properties due to their sharp apexes, large aspect ratios and well alignment on substrate (1). However, in comparison with carbon nanotubes, the field emission properties of the AlN nanocone arrays were not so promising because of their wide band gap and large density. To further improve the field emission properties of AlN nanocones, two means are worthy of attempt. One is to increase the conductivity of AlN nanocones by doping other elements or constructing composite nanostructures, and the other is to adjust the nanocone density to decrease the screening effect.

Modified redox synthesis and electrochemical properties of potassium manganese oxide nanowires

A convenient hydrothermal method has been developed for the controllable synthesis of various nanostructures of manganese oxides and their derivatives through modified redox reactions between Mn2+ and the combinative oxidizer of KBrO3/KX (X = Cl, Br, I). The morphologies and oxidation states of the products could be modulated simply by changing the anions in KX to regulate the oxidizability of the combinative oxidizer. With KBrO3/KBr as the oxidizer, potassium manganese oxide (KMO) nanowires are obtained owing to the appropriate oxidizability of the oxidizer as well as the assistance of ion-intercalated effect. The KMO nanowires exhibit the electrochemical capacitance of about 134.2 F g−1 at the scan rate of 10 mV s−1 and superior cycling stability as revealed by cyclic voltammetry and charge/discharge measurements, implying their potential application in supercapacitors for electrical storage.

Electrocatalysts: Facile Construction of Pt–Co/CNx Nanotube Electrocatalysts and Their Application to the Oxygen Reduction Reaction (Adv. Mater. 48/2009)

Pt-Co alloyed nanoparticles can be facilely immobilized onto CNx nanotubes due to the incorporated nitrogen, report Yanwen Ma, Zheng Hu, and co-workers on p. 4953. The as-prepared electrocatalysts exhibit good performance for oxygen reduction reactions in acidic media arising from the high dispersion and alloying effect of Pt-Co nanoparticles, as well as the intrinsic catalytic capacity of CNx nanotubes, which is significant for the development of fuel cells.