Enhanced methanol oxidation activity of PtRu/C100−xMWCNTSx (x = 0–100 wt.%) by controlling the composition of C‐MWCNTs support

Abstract

PtRu nanoparticles decorated on carbon‐based supports are of great interest for direct methanol fuel cells (DMFCs). In this study, PtRu alloy nanoparticles decorated on carbon Vulcan XC‐72 (C), multi‐walled carbon nanotubes (MWCNTs), and C‐MWCNTs composite supports were synthesized by co‐reduction method. As a result, PtRu nanoparticles obtained a small mean size (dmean = 1.8–3.8 nm) with a size distribution of 1–7 nm. We found that PtRu/C60MWCNTS40 possesses not only high methanol oxidation activity, but also excellent carbonaceous species tolerance ability, suggesting that C‐MWCNTs composite support is better than either C or MWCNTs support. Fur-thermore, detailed investigation on PtRu/C100−xMWCNTSx (x = 10–50 wt.%) shows that the current density (Jf), catalyst tolerance ratio (Jf/Jr), and electron transfer resistance (Ret) are strongly affected by C‐MWCNTs composition. The highest Jf is obtained for PtRu/C70MWCNTS30, which is considered as an optimal electrocatalyst. Meanwhile, both PtRu/C70MWCNTS30 and PtRu/C60MWCNTS40 ex-hibit a low Ret of 5.31–6.37 Ω∙cm2. It is found that C‐MWCNTs composite support is better than either C or MWCNTs support in terms of simultaneously achieving the enhanced methanol oxidation activity and good carbonaceous species tolerance.