Abstract
We report here the synthesis of metal oxide nanosheets (MONs) directly grown on stainless steel substrates by thermal oxidation in the presence of trace amounts of water. The morphology and microstructure of MONs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and atomic force microscopy (AFM). The composition of MONs was determined by the energy dispersive system and X-ray diffraction patterns. The results showed that the as-synthesized MONs were ultrathin, vertically aligned, and mostly transparent. They were polycrystalline and were composed primarily of Cr2O3 and (Fe, Mn)3O4. The optimal condition to synthesize the MONs with an optimal ultra-high surface atom ratio were determined by varying the temperature and time required for the growth of the MONs. It was found that the lateral size of MONs gradually increases as the temperature rises from 1000 to 1100 °C. An optimal temperature of 1100 °C is obtained in terms of the growth density, size and transparency degree growth morphology, and quality. The structure of MONs changes from two-dimensional to three-dimensional networks when the synthesis time is prolonged to more than 1 h.
Highlights
Over the past decade metal oxides have sparked tremendous interest, owing to their unique physical and chemical properties, including wide band gap [1,2], reactive electronic transitions [3,4], and good electrical, optical characteristics [5,6,7,8]; this interest continues to grow
The effect of the experimental conditions and environment on the growth morphology and quality of Elemental analysis of the specimens was performed with an energy dispersive system (EDS) attached the specimens
Vertically oriented metal oxide nanosheets (MONs) are directly synthesized by a one-step thermal oxidation
Summary
Over the past decade metal oxides have sparked tremendous interest, owing to their unique physical and chemical properties, including wide band gap [1,2], reactive electronic transitions [3,4], and good electrical, optical characteristics [5,6,7,8]; this interest continues to grow. Two-dimensional (2D) metal oxide nanosheets (MONs) have emerged as the new members of the metal oxide nanomaterials family and the high surface area of these 2D structures has been exploited in electrochemical applications such as lithium batteries and supercapacitors by numerous groups [24,25]. We report here for the first time a one-step atmospheric pressure water-assisted thermal oxidation process to fabricate ultrathin nanosheets, mainly composed of Cr2 O3 and (Fe, Mn) O4 , on stainless steel mesh or foil. In this contribution, the metal oxide nanosheets were directly prepared by using a simple and facile technique, consisting of a quartz tube furnace connected to a gas manifold for controlling the gas flow rate and composition.
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