Micropore‐Rich Carbon‐Confined Pt as the Phosphoric Acid Poisoning‐Resistant Electrocatalyst for Oxygen Reduction Reaction

The H 3 PO 4 poisoning problem severely limits the performance of high‐temperature proton exchange membrane fuel cells (HT‐PEMFCs) using the H 3 PO 4 ‐doped polybenzimidazole as electrolyte membrane. Herein, the micropore‐rich carbon shell‐confined Pt‐based nanoparticles (Pt@MPC) with a Pt loading of 44.9 wt% is developed as the H 3 PO 4 poisoning‐resistant electrocatalyst for oxygen reduction reaction (ORR), which possesses both high ORR activity and stability. The half‐wave potential ( E 1/2 ) of 0.898 V and electrochemical active surface area (ECSA) of 62.3 m 2 g Pt −1 are superior to commercial 40 wt% Pt/C ( E 1/2 = 0.892 V; ECSA = 53.1 m 2 g Pt −1 ). Pt@MPC remains almost unchanged after the accelerated durability test of 10 000 cycles. Moreover, Pt@MPC exhibits remarkable H 3 PO 4 tolerance as its negative shift of E 1/2 (82 mV) is less in H 3 PO 4 ‐containing electrolyte compared with commercial Pt/C (114 mV). This can be attributed to the steric effect of the micropore‐rich carbon, which enables the selective transport of reactants while inhibiting H 3 PO 4 . The HT‐PEMFCs assembled with Pt@MPC (0.7 mg Pt cm −2 ) exhibit a maximum power density of 674 mW cm −2 under the H 2 ‐O 2 condition and outperform the commercial Pt/C (616 mW cm −2 ). This strategy provides a new direction for the design of ORR catalysts toward HT‐PEMFCs with better phosphoric acid poisoning resistance.