Chapters authored
Noble Metal Dispersed on Reduced Graphene Oxide and Its Application in PEM Fuel Cells
Metal-dispersed nanoparticles on reduced graphene oxide as catalyst for oxygen reduction reaction (ORR) demonstrate promising applications in the energy sector. The catalyst activity enhancement and stability improvement investigated in this study are mandatory steps in obtaining feasible electrodes for PEMFC. The chapter deals with the synthesis of noble metal catalysts including platinum and gold nanoparticles dispersed on reduced graphene oxide (PtNPs/rGO and AuNPs/rGrO). The understanding of the correlations between the electrochemical activity on one side and the structure, composition and synthesis method on the other side are provided. Facile routes in order to prepare the well dispersed PtNPs/rGO and AuNPs/rGrO are included. The structure and morphology were characterized by different techniques, namely X-ray diffraction (XRD), Scanning Transmission Electron Microscopy (STEM), specific surface area measurements. In this context we report a hybrid derived electrocatalyst with increased electrochemical active area and enhanced mass-transport properties. The electrochemical performances of PtNPs/rGO and AuNPs/rGrO were tested and compared with a standard PEMFC configuration. The performed electrochemical characterization recommends the prepared materials as ORR electrocatalysts for the further fabrication of cathodes for PEM fuel cells. The research directions as well as perspectives on the subsequent development of more active and less expensive electrocatalysts are established.
Part of the book: Electrocatalysts for Fuel Cells and Hydrogen Evolution
Synthesis and Functionalization of Nanoparticles in Supercritical CO2
A review of recent results on fabrication of inorganic and organic nanoparticles in supercritical carbon dioxide will be presented, with particular emphasis on the metallic and polymeric nanoparticles used in biomedicine. The use of the water-in-scCO2 microemulsion in the synthesis of metal nanoparticles will be also discussed. The recent progress in preparation of polymeric nanoparticles with desired size and porosity obtained through processing methods in scCO2 as drug delivery systems will be described. The efficiency of the drug encapsulation in organic and inorganic nanoparticles using supercritical CO2 as dissolving media is another topic of interest. Various methods to achieve surface functionalization of nanoparticles in supercritical and subcritical CO2 will be evaluated, considering the challenges and limitations in efficiency, scalability, and development of new applications.
Part of the book: Advanced Supercritical Fluids Technologies