Studies On Preparation Of Functional Metal Oxides Nanomaterials Via Dielectric Barrier Discharge Plasma

ZnO and MnO2nanomaterials have been widely used in many fields because oftheir special properties. Different preparation methods can prepare nanomaterials withdifferent morphologies、structures and properties, so the preparation of the ZnO andMnO2nanomaterials has attracted much attention. The dielectric barrier discharge(DBD) plasma has been recognized as a new green method for nanomaterialspreparation, which can endow the products with unique nature. In the present work,ZnO and MnO2nanomaterials are prepared via DBD plasma respectively, XRD, TEMetc. are used to characterize the physical and chemical performance of the synthesizedmaterials. For comparison, thermal decomposition is also used to prepare the twomaterials.The results show that ZnO samples in a hexagonal wurtzite phase are obtainedboth by the DBD plasma decomposition and thermal decomposition of Zn(OH)2. TheZnO-DBD presents the morphology of hexagonal hollow nanotube, which growsalong the c-axis direction. On the other hand, one of the growth planes of the ZnO-Cis along the (101) plane, which is demonstrated to be nanoparticles. Low-temperatureH2S removal is conducted to compare the desulfurization performance of the twosamples. The DBD plasma made ZnO nanotube shows a higher performance for H2Sremoval at low temperature compared with the ZnO-C nanoparticles. The H2S DRIFTspectra demonstrate that there are more surface hydroxyl groups reacting with H2Sgas on the ZnO-DBD surface, that’s why ZnO-DBD has an enhanced desulfurizationperformance. In addition, the growth mechanism of the ZnO nanotube is also putforward.Birnessite MnO2samples with a layer spacing d=7.16935are obtained byDBD plasma decomposition and thermal decomposition of KMnO4.The preparedMnO2samples contain K+and H2O inserted into the interlayer space, which is helpfulto maintain the stability of the layer structure. FESEM results show the MnO2-DBD isa curly nanosheet structure, while the MnO2-C presents irregular morphology. Thelayer spacing, i.e. the d spacing can be observed via the HRTEM, and the layerspacing of MnO2-DBD is more regular than that of MnO2-C. BET results show thatthe surface area of MnO2-DBD is slightly larger than that of MnO2-C, they have a similar pore size of38.6, demonstrated to be mesoporous materials. The CVanalysis results show that the MnO2-DBD is more conducive for the embedding andextraction of K+. It may because the MnO2-DBD has a larger surface area and alamellar structure which is helpful for the movement of ions. Moreover, we bringforth the formation mechanism of the MnO2-DBD nanosheets.