Last modified: 2014-09-29
Abstract
Polymer electrolyte membrane fuel cell (PEMFCs) are promising electrochemical devices for the direct conversion of chemical energy of hydrogen into electrical work. However, besides high cost owing to a low utilization of the noble metal catalyst (i.e., Pt), the low stability owing to sensitive oxidation of conventional carbon black supports under radically chemical and electrochemical oxidation conditions at cathode for fuel cells, as well as the low tolerance towards SO2, have seriously hindered the commercialization of PEMFCs. Thus, in this work, the simple blend of silicon carbides and carbon nanospheres (CNS) is present and shows an enhanced catalytic activity and stability in comparison with pristine silicon carbide as the catalyst supports. And then ZrO2 is used to decorate the surface of CNS to improve the electrochemical stability of carbon supports. Especially, a novel conductive ceramic/graphene nanohybrid is prepared to prohibit the re-stacking of reduced graphene oxide (RGO) by wedging zirconium diboride (ZrB2) nanoparticles (NPs) into multiple layer nanosheets using a simple solvothermal method. The prepared Pt/RGO-ZrB2 catalyst shows very excellent catalytic activity and electrochemical stability. Finally, WOx and CeO2 are adopted, respectively, to modify the CNS supported noble metal catalysts with an aim of acquiring the excellent sulfur tolerance since its unique nature in hydrophily, redox couple in lower valence as well as proton spillover effect. The remarkably improved electrochemical properties with much high Pt utilization of the above new catalysts show a promising application in PEMFCs and broader fields.