Improvement of ORR Activity of Monoclinic Zirconium Oxides by Fe and F Co-addition for PEFC Cathodes (Supporting Information)

We investigated the effect of adding Fe and F in the synthesis of zirconium-oxide-based cathode precursors to enhance the catalytic activity in the oxygen reduction reaction (ORR) in acidic media. In particular, we focused on adding F, and an ORR onset potential of 0.88 V was achieved by optimizing the amount of F added and heat treatment conditions contrary to a reversible hydrogen electrode. Additionally, a positive linear relationship was observed between the ORR onset potential and integrated intensity ratio of the monoclinic phase of ZrO2 in the catalysts. This suggests that the monoclinic phase is fundamentally involved in the formation of active sites in the ORR in zirconium oxide-based cathodes.

本研究探讨了在合成氧化锆基阴极前驱体过程中添加铁（Fe）和氟（F）对酸性介质中氧还原反应（ORR）催化活性的影响。特别是，我们专注于氟的添加，并通过优化氟的添加量和热处理条件，成功实现了0.88 V的氧还原反应起始电位，这一结果与可逆氢电极相反。此外，观察到氧还原反应起始电位与催化剂中氧化锆单斜相的积分强度比之间存在正相关关系。这一发现表明，单斜相在氧化锆基阴极中ORR活性位点的形成过程中起着根本性的作用。