Abstract
A gas-phase-controlled self-assembly synthetic approach is demonstrated to fabricate functional hybrid nanoparticles for energy and environmental applications. TGA, XRD, SEM, in-situ DMA, HR-TEM and EDS were demonstrated for characterization of synthesized hybrid nanoparticles. In our work, the self-assembly hybrid-nanoparticles were used as photocatalysts and electrode materials for photodegradation techniques and supercapacitors application, respectively. In the first part of the work, we use aerosol-based self-assembly approach to fabricate Ag-ZnO hybrid nanostructure as a high-performance catalyst for photodegradation of water pollutants. The degradation of rhodamine B (RhB) was used as representative, which were tested and evaluated with respect to the environmental pH and the presence of dodecyl sulfate corona on the surface of the catalyst. The results show that a raspberry-structure Ag−ZnO hybrid nanoparticle cluster was successfully synthesized via gas-phase evaporation-induced self-assembly. The photodegradation activity increased significantly (20×) by using the Ag−ZnO hybrid nanoparticle cluster as a catalyst. A surge of catalytic turnover frequency of ZnO nanoparticle cluster (>20×) was observed through the hybridization with silver nanoparticles. The dodecyl sulfate corona increased the photocatalytic activity of the Ag−ZnO hybrid nanoparticle cluster, especially at the acidic and neutral pH environments (maximum 6×), and the enhancement in catalytic activity was attributed to the improved colloidal stability of ZnO-based nanoparticle cluster under the interaction with RhB. This part provides a generic route of facile synthesis of the Ag−ZnO hybrid nanoparticle cluster with a mechanistic understanding of the interface reaction for enhancing photocatalysis toward the degradation of water pollutants. We use the same gas-phase controlled method to fabricate AgMnOx hybrid nanostructures. TGA、XRD、SEM、EDS and in-situ DMA were demonstrated to characterize properties of hybrid nanostructures. Ag nanoparticles were homogeneously distributed outside the MnOx nanoparticle cluster. AgMnOx hybrid nanoparticles were used as electrode materials for supercapacitors application. Supercapacitor performances are influenced by binder types and contents in the electrodes. We performed two types of binder solutions: nafion and PVDF. The capacitance performance of different types of binders were investigated by cyclic voltammetry (CV) and galvanostatic charge discharge (GCD). The results showed that PVDF was suitable binder than nafion based on its higher dispersibility and better electrochemical performances. The specific capacitance of electrodes using PVDF as binder can reach 210 F/g (maxima). The increasing specific capacitance was also observed through the hybridization with silver nanoparticles. After addition of carbon black. The specific capacitance of AgMnOx reached 325 F/g (maxima) after adding carbon black. The high performance of the hybrid nanoparticle as the electrode was attributed to the better conductivities during the electrochemical reaction. We provide a facile aerosol-based synthesis method to fabricate hybrid nanoparticles as electrode materials for enhancing the specific capacitance.