Self-assembled CeO₂ on carbon nanotubes supported Au nanoclusters as superior electrocatalysts for glycerol oxidation reaction of fuel cells

One of the critical challenges in energy conversion using fuel cells is the development of non-Pt based electrocatalysts with high activity and stability. Herein, CeO₂ nanoclusters of 1.5 nm supported on 1-pyrenecarboxylic acid (PC) functionalized multi-walled carbon nanotubes (PC-MWNTs) were synthesized via sequential polyelectrolyte functionalization and microwave-assisted self-assembly, and subsequently used as a support of gold (Au) NPs for glycerol oxidation reaction. The hybrid Au/CeO₂/PC-MWNT electrocatalyst shows excellent activity and durability, achieving a peak current density 28 times that of the commercial Pt/C catalyst; at a practical fuel cell operation potential of -0.3 V vs. SCE, it exhibits a current density 1.6 times that of Pt/C. In addition, after polarization at -0.3 V vs. SCE for 1800s, the current density is 2.5 times that of Pt/C. This is probably the first report of a higher catalytic performance of Au-based catalysts than that of the commercial Pt/C catalysts at practical fuel cell operation potentials. The work not only provides an economical and facile strategy to synthesize oxide-based nanoclusters (NP size < 2 nm) as a support of Au-based electrocatalysis, but also offers a superior electrocatalyst to replace Pt-based ones for glycerol oxidation reaction in glycerol fuel-based direct alcohol fuel cells.