Improvement in stability of PtRu electrocatalyst by carbonization of in-situ polymerized polyaniline

As well known, ruthenium is electrochemically unstable in direct methanol fuel cell (DMFC) operation shortening lifetime and deteriorating performance of DMFC device. In this work, a facile methodology for improvement in stability of PtRu electrocatalyst is described, in which PtRu alloyed nanoparticles are decorated by nitrogen-doped carbon (NxC) originating from the carburization of in-situ polymerized polyaniline (PANI). Deceleration in Ru dissolution of NxC protected PtRu electrocatalyst comes from the ionized Ru atoms induced by the carburization of PANI transferring electrons from Ru to nitrogen atoms evidenced by XPS measurement, which results in higher CO tolerance during potential sweeping from 0.6 to 1.0 V versus RHE for NxC decorated PtRu electrocatalyst. Meanwhile, NxC protected PtRu electrocatalyst only losses 10% of active sites after stability estimation; in contrast, 50% of active sites are lost for bare PtRu electrocatalyst. Moreover, fuel cell test illustrates that NxC protected PtRu electrocatalyst shows comparable performance to bare PtRu electrocatalyst.