TiN as Radical Scavenger in Fe─N─C Aerogel Oxygen Reduction Catalyst for Durable Fuel Cell
Yi Luo, Ke Li, Yijie Hu, Teng Chen, Qichen Wang, Jianqiang Hu, Jian Feng, Jian Feng, Junzong Feng, Junzong Feng
Abstract
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.