TiN as Radical Scavenger in Fe─N─C Aerogel Oxygen Reduction Catalyst for Durable Fuel Cell

Abstract Fe─N─C is the most promising alternative to platinum‐based catalysts to lower the cost of proton‐exchange‐membrane fuel cell (PEMFC). However, the deficient durability of Fe─N─C has hindered their application. Herein, a TiN‐doped Fe─N─C (Fe─N─C/TiN) is elaborately synthesized via the sol–gel method for the oxygen‐reduction reaction (ORR) in PEMFC. The interpenetrating network composed by Fe─N─C and TiN can simultaneously eliminate the free radical intermediates while maintaining the high ORR activity. As a result, the H 2 O 2 yields of Fe─N─C/TiN are suppressed below 4%, ≈4 times lower than the Fe─N─C, and the half‐wave potential only lost 15 mV after 30 kilo‐cycle accelerated durability test (ADT). In a H 2 ─O 2 fuel cell assembled with Fe─N─C/TiN, it presents 980 mA cm −2 current density at 0.6 V, 880 mW cm −2 peak power density, and only 17 mV voltage loss at 0.80 A cm −2 after 10 kilo‐cycle ADT. The experiment and calculation results prove that the TiN has a strong adsorption interaction for the free radical intermediates (such as *OH, *OOH, etc.), and the radicals are scavenged subsequently. The rational integration of Fe single‐atom, TiN radical scavenger, and highly porous network adequately utilize the intrinsic advantages of composite structure, enabling a durable and active Pt‐metal‐free catalyst for PEMFC.