Worm-like PtP nanocrystals supported on NiCo2Px/C composites for enhanced methanol electrooxidation performance

Abstract

Worm-like PtP nanocrystals supported on NiCo2Px/carbon black (NiCo2Px/C) composites were prepared by a combined hydrothermal, low temperature phosphidation and NaBH4 reduction process. Noteworthily, the presence and content of phosphorus (P) play a critical role in constructing one-dimensional (1D) PtP nanostructures. Electrochemical tests demonstrate that the obtained PtP-NiCo2Px/C hybrid exhibits an extremely high mass activity of 1361 mA mg−1Pt for methanol electrooxidation in acidic medium, which is 3.5- and 7.6-fold greater than those of commercial Pt/C (393 mA mg−1Pt) and home-made Pt/C catalyst (180 mA mg−1Pt), respectively. Meanwhile, the catalytic performence of PtP-NiCo2Px/C is also better than those of the PtP-CoP/C and PtP-Ni2P/C catalysts due to the synergistic effect of Co and Ni. Furthermore, PtP-NiCo2Px/C catalyst exhibited better durability and CO tolerance compared with other catalysts in this study. The enhanced catalytic performence of PtP-NiCo2Px/C hybrid can be attributed to the special 1D morphology of PtP nanocrystals, the strong interaction between catalytic species and support, as well as the existence of metal center (Mδ+, M = Ni or Co) and Pδ− active sites for the dissociation of H2O molecules. The design of 1D PtP alloy nanostructures and co-catalytic effect of NiCo2Px provides a promising method to significantly improve methanol oxidation performence.