Electrochemical performance of Pt-based catalysts supported on different ordered mesoporous carbons (Pt/OMCs) for oxygen reduction reaction

The present work aims to compare and evaluate the behavior of platinum catalysts supported on different ordered mesoporous carbons (Pt/OMCs). OMCs were templated from two kinds of ordered mesoporous silicas (2-D SBA-15 and 3-D SBA-16), with sucrose as carbon precursor and boric acid as a pore expanding agent. Structural characterizations revealed that all OMCs inherited the structure from silica templates. OMC synthesized from a mixture of sucrose and boric acid exhibited a larger pore size. According to XRD, TEM, and XPS analysis, particle size and distribution of Pt were influenced by the porosity of OMC supports. In single PEMFC tests, catalysts supported on OMC with a 3-D pore structure (Pt/C16sucr: 0.57 W cm-2 at 0.45 V) or with 2-D larger pores (Pt/C15sucr+B: 0.44 W cm-2 at 0.45 V) significantly enhanced the FC performance compared to Pt/C15sucr (0.29 W cm-2 at 0.45 V), which may be attributed to a better mass transfer and a higher catalytic activity. In particular, it was found that Pt/C16sucr had a catalytic behavior superior to that of the Pt/Vulcan commercial catalyst in the high potential region, suggesting that C16sucr is a promising catalyst support for PEMFC application.