Integrating Pt–Co Nanoalloy and Sulfur-Doped Co–N–C to Construct Oxygen Reduction Reaction Catalysts for Proton Exchange Membrane Fuel Cells

Abstract

Achieving high catalytic activity and stability with low platinum loading is vital for reducing the cost of proton exchange membrane fuel cells (PEMFCs) and enabling their large-scale commercialization. Herein, a three-dimensional (3D) nitrogen sulfur codoped carbon nanocomposite support embedded with Co nanoparticles derived from sulfur-doped zeolite imidazolate frameworks-67 was synthesized. After Pt nanoparticles are loaded, it can act as an excellent ORR catalyst (3D LPCNSC) for hydrogen–oxygen fuel cells. The existing metal Co are beneficial for catalyzing the growth of carbon nanotubes, generating CoN_x structures, and partially forming Pt–Co nanoalloys. Nitrogen sulfur codoping can enhance metal–support interactions between Pt/Pt–Co and sulfur-doped Co–N–C by regulating the interfacial charge transfer. The 3D conductive network constructed using graphene oxide and carbon nanotubes contributes to enhanced electron and mass transfer. As a result, the 3D LPCNSC catalyst with a relatively lower Pt loading (13.65%) exhibits a superior half-potential, higher mass activity, and superb stability in comparison to commercial Pt/C (20%). A membrane electrode assembly assembled with this catalyst achieves a peak power density of 983.8 mW cm^–2 in a hydrogen–oxygen single cell. This work highlights a promising avenue for the structure and component design of low platinum nanocatalyst for PEMFCs.