Oxidation Mechanism of Nickel Oxide/Carbon Nanotube Composite

Abstract

Abstract:The oxidation mechanism and thermal stability of nickel oxide~NiO!/carbon nanotube~CNT! composites were investigated by examining composites with different NiO contents by thermogravimetric analysis and transmission electron microscopy~TEM!. NiO acts as a catalyst in the oxidation of CNT in the composite. CNTs can be oxidized, even in a vacuum, by reducing NiO to nickel at temperatures lower than the normal oxidation temperature of CNTs. This phase transition was confirmed directly by in situ heating TEM observations. In air, reduction by CNT occurs simultaneously with reoxidation by gaseous O 2 molecules, and NiO maintains its phase. The thermal stability decreased with increasing NiO content because of defects in the CNT generated by the NiO loading.

Low-temperature conversion of CaO-captured CO2 to CH4 over a greenly prepared Ni/CaO/Al2O3 composite under static pressure conditions

“…It was reported that O ads on the surface of the catalyst is favorable for reduction and oxidation processes. 39 Two characteristic peaks appeared in the Ca 2p spectrum (Fig. 3d), which belonged to calcium oxide (∼346.5 eV) and residual carbonate (∼350.5 eV).…”

“…3a). 39 Two characteristic peaks appeared in the Ca 2p spectrum (Fig. 3d), which belonged to calcium oxide (∼346.5 eV) and residual carbonate (∼350.5 eV).…”

Morphological Analysis of the Amorphous Carbon Embedded Nickel-Silica Composite Submitted at Gradual Oxidation

“…Above 650°C, the oxidation rate is more dependent of thickness of oxygen gas film over the material surface, which is thicker as higher the gas pressure. The oxidation mechanisms of carbon phase have rate-controlled steps at temperatures ranging between 400 and 800°C and depend on activation energies originated from different composite morphologies [13][14].…”