Fe2O3@FeP core-shell nanocubes/C composites supported irregular PtP nanocrystals for enhanced catalytic methanol oxidation

Abstract

The construction of highly active Pt-based catalyst for methanol electrooxidation is still an ongoing challenge. Herein, irregular PtP nanocrystals with the length is around 7 nm supported on the Fe2O3@FeP/C composites consisting of Fe2O3@FeP core-shell nanocubes and carbon black particles are synthesized by an integrated hydrothermal, low temperature phosphidation and NaBH4 reduction process. TEM and EDS reveal that both the presence of phosphorus (P) and the mild Pt reduction method are play a critical role in constructing irregular PtP nanocrystals. Interestingly enough, the confinement effect of carbon particles on iron ions in the process of hydrothermal reaction leads to the generation of Fe-precursor nanocubes. Benefiting from the P can effectively modify the electronic state of the Pt surface, the strong interaction between special irregular PtP nanocrystals and the support surface as well as Fe2O3@FeP core-shell nanocubes for the enhanced activation and decomposition of H2O molecules, the as-prepared PtP-Fe2O3@FeP/C-8 h catalyst exhibits better anti-CO poisoning ability, stability and excellent catalytic activity for methanol oxidation. Specifically, the mass activity (831 mA mg−1Pt) of PtP-Fe2O3@FeP/C-8 h is 4.6- and 2.1-times greater than that of home-made Pt/C (Pt/C-H) (180 mA mg−1Pt) and commercial Pt/C (Pt/C-JM) (393 mA mg−1Pt) catalyst in acidic medium. At the same time, the mass activity of PtP-Fe2O3@FeP/C-8 h is as high as 3215 mA mg−1Pt, which is much higher than those of Pt/C-H (1298 mA mg−1Pt) and Pt/C-JM (1548 mA mg−1Pt) catalysts in alkaline medium. The present work provides a new entry points into the synthetic way for the irregular PtP nanocrystals and cheap co-catalytic species for methanol oxidation reaction (MOR).