Highly loaded fine PtCo intermetallic compounds on 3D N-doped porous graphene for enhanced sustained efficiency in PEMFCs

Abstract

Currently, carbon supports are subject to carbon corrosion during repetitive start-up and shut-down processes in proton exchange membrane fuel cells (PEMFCs), causing performance degradation. To address this issue, we have developed a highly graphitized and nitrogen-doped graphene (HGNG) produced by a plasma-enhanced chemical vapor deposition (PECVD) strategy, accompanied by high-temperature treatment and ammonia plasma treatment. The HGNG features a three-dimensional hierarchical porous structure with a high specific surface area, a high degree of graphitization, and a considerable quantity of nitrogen doping, as well as a high Pt load (49.8 wt.%) of L10-PtCo nanoparticles (NPs) that are uniformly distributed in the structure. As a result, the L10-PtCo/HGNG catalyst exhibits excellent oxygen reduction (ORR) activity and durability in PEMFC, with both catalyst and support durability exceeding the DOE 2025 target. Impressively, the L10-PtCo/HGNG catalyst achieves a power density of 964 mW cm-2 in the H2-Air fuel cell with only 19 mV and 17 mV loss at 0.8 A cm-2 and 1.5 A cm-2 after accelerated durability tests of both electrocatalyst and support, respectively, which are less than the DOE target of 30 mV loss. This study lays the foundation for designing efficient and durable catalysts for practical applications in PEMFCs.