Secondary reduction strategy synthesis of Pt-Co nanoparticle catalysts towards enhanced the activity of proton exchange membrane fuel cells

Based on the volcanic relationship between catalytic activity and key adsorption energies, Pt-Co alloy materials have been widely studied as cathode oxygen reduction reaction (ORR) catalysts in proton exchange membrane fuel cells (PEMFCs) due to their higher active surface area and adjustable D-band energy levels compared to Pt/C. However, how to balance the alloying degree and ORR performance of Pt-Co catalyst remains a great challenge. Herein, we first synthesized a well-dispersed Pt/Co/C precursor by using a mild dimethylamine borane (DMAB) as the reducing agent. The precursor was calcined at high temperature under H2/Ar mixed gas by a secondary reduction strategy to obtain an ordered Pt3Co intermetallic compound nanoparticle catalyst with a high degree of alloying. The optimization of electronic structure due to Pt-Co alloying and the strong metal-carrier interaction ensure the high kinetic activity of the cell membrane electrode. Additionally, the high degree of graphitization increases the electrical conductivity during the reaction. As a result, the activity and stability of the catalyst were significantly improved, with a half-wave potential as high as 0.87 V, which decreased by only 20 mV after 10000 potential cycles. Single-cell tests further validate the high intrinsic activity of the ordered Pt3Co catalyst with mass activity up to 0.67 A mgpt–1, exceeding the United States Department of Energy (US DOE) standard (0.44 A mgpt–1), and a rated power of 5.93 W mgpt–1.