Electrochemically corroded thick microporous N[sbnd]C layer encapsulated Pt/C as highly active and ultra-highly stable electrocatalyst for methanol oxidation and oxygen reduction reaction in acidic media

Abstract

We demonstrate that electrochemically corroded thick nitrogen-doped carbon (NC) layer encapsulated Pt/C (denoted as NC/Pt/C) has high activity and ultrahigh stability for both methanol oxidation and oxygen reduction reactions. The encapsulation of thick NC layers leads to very low initial activities due to tight coverage; however, after 80,000 cyclic voltammetry (CV) cycles of aging corrosion process, the activities increase to 2–3 times that of bare Pt/C and keep almost unchanged for next 50,000 CV cycles. In H2/O2 acidic membrane fuel cell with NC/Pt/C as cathode, high power densities (1.34–1.39 W cm−2) can be kept for 50,000 cycles, ranking it one of the most stable noble metal catalysts. The thick NC layers are corroded to be more microporous during the electrochemical aging process; the resultant micropores favor mass transport and can still closely bind and protect Pt particles within a long operation time, leading to the improved activity and stability.