Narrow Results

ZnO nanoneedle arrays were obtained from the transformation of ZnC₂O₄ precipitate, which was synthesized via electrodeposited method at room temperature. The diameter of those grown ZnO nanoneedles is about 80 nm. The XRD pattern and the HRTEM image indicate that the grown ZnO nanoneedles have the preferential growth toward (101) direction. The possible growth mechanism of the ZnC₂O₄ nanoneedle arrays is proposed and is different from the traditional V-L-S and V-S models. The study on the PL spectrum of those ZnO nanoneedles shows the near band-edge emission band (379 nm) and the green emission band (510 nm). Especially, a red shift of the green emission band emerges with the increase of the annealing temperature and time.

3D structure composite made of tiny basic nickel carbonate arrays on the surface of reduced graphene oxide nanosheets (G-NiCH) are prepared by the hydrothermal method. The specific surface area of the G-NiCH composites is twice that of single basic nickel carbonate, which is due to the tiny basic nickel carbonate arrays structure wherein each individual nanoneedle is about 20nm in length and 2nm in width. The G-NiCH electrodes display high-efficiency electrochemical performance with good specific capacitance (1230Fg${}^{-1}$) and excellent stability (100% capacitance retention after 2000 cycles). This is attributed to the synergistic effect that reduced graphene oxide offer fast electron transmission path and basic nickel carbonate act as high effective active material.