Enhanced Activity of Small Pt Nanoparticles Decorated with High‐Loading Single Fe─N<sub>4</sub> for Methanol Oxidation and Oxygen Reduction via the Assistive Active Sites Strategy
Wei Yan, Qianli Xing, Jianwei Ren, Feng Hao, Jinshi Yu, Hao Liu, Wenmiao Chen, Kang Wang, Yanli Chen
Abstract
Abstract Decorating platinum (Pt) with a single atom offers a promising approach to tailoring their catalytic activity. In this study, for the first time, an innovative assistive active sites (AAS) strategy is proposed to construct high–loading (3.46wt.%) single Fe─N 4 as AAS, which are further hybridized with small Pt nanoparticles to enhance both oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR) activities. For ORR, the target catalyst (Pt/HFe SA –HCS) exhibits a higher mass activity (MA) of 0.98 A mg Pt −1 and specific activity (SA) of 1.39 mA cm Pt −2 at 0.90 V versus RHE. As for MOR, Pt/HFe SA –HCS shows exceptional MA (3.21 A mg Pt −1 ) and SA (4.27 mA cm Pt −2 ) at peak values, surpassing commercial Pt/C by 15.3 and 11.5 times, respectively. The underlying mechanism behind this AAS strategy is to find that in MOR, Fe─N 4 promotes water dissociation, generating more *OH to accelerate the conversion of *CO to CO 2 . Meanwhile, in ORR, Fe─N 4 acts as a competitor to adsorb *OH, weakening Pt─OH bonding and facilitating desorption of *OH on the Pt surface. Constructing AAS that can enhance dual functionality simultaneously can be seen as a successful “kill two birds with one stone” strategy.