PtCo/N-doped carbon sheets derived from a simple pyrolysis of graphene oxide/ZIF-67/H2PtCl6 composites as an efficient catalyst for methanol electro-oxidation

Abstract

Many alloy catalysts have been developed for methanol electro-oxidation, but most synthetic methods are complicated. Herein, PtCo alloy catalysts supported on N-doped carbon sheets (PtCo/NCS) are successfully prepared by a simple pyrolysis of graphene oxide/ZIF-67/H2PtCl6 composites at different temperatures (700, 800, 900 °C) under a gas flow of H2/Ar, in which ZIF-67 is served as Co and N sources. SEM, TEM, XRD, XPS and electrochemical characterization are employed to study as-prepared catalysts. In acidic methanol solution, the area-specific activity (1.25 mA cm−2 Pt) of PtCo alloy catalyst obtained at 800 °C (PtCo/NCS-800) is 2.6 times of commercial Pt/C (0.48 mA cm−2 Pt), and the area-specific activity of PtCo/NCS-800 is 3.5 times of Pt/C after 1000 cycles. Furthermore, an improved CO-tolerance of Pt is confirmed. The electronic effect and synergistic effect of metallic elements are responsible for outstanding performance of as-prepared catalysts. This work provides a simple approach to obtain high performance alloy catalysts.