Enhanced Activity of Small Pt Nanoparticles Decorated with High-Loading Single Fe─N 4 for Methanol Oxidation and Oxygen Reduction via the Assistive Active Sites Strategy

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 20; no. 14; p. e2308473
• Main Authors: Yan, Wei, Xing, Qianli, Ren, Jianwei, Feng, Hao, Yu, Jinshi, Liu, Hao, Chen, Wenmiao, Wang, Kang, Chen, Yanli
• Format: Journal Article
• Language: English
• Published: Germany 01.04.2024
• Subjects: platinum; methanol oxidation reaction (MOR); oxygen reduction reaction (ORR); porous organic polymers; single atom catalysts
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202308473

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 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 -HCS) exhibits a higher mass activity (MA) of 0.98 A mg and specific activity (SA) of 1.39 mA cm at 0.90 V versus RHE. As for MOR, Pt/HFe -HCS shows exceptional MA (3.21 A mg ) and SA (4.27 mA cm ) 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 promotes water dissociation, generating more *OH to accelerate the conversion of *CO to CO . Meanwhile, in ORR, Fe─N 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.