Boosting the activity of non-platinum group metal electrocatalyst for the reduction of oxygen via dual-ligated atomically dispersed precursors immobilized on carbon supports

• Published in: Nano energy 2021-12, Vol.90 (Part: A), p.106547, Article 106547
• Main Authors: Zhou, Yu, Al-Zoubi, Talha, Ma, Yanling, Hsiao, Haw-Wen, Zhang, Cheng, Sun, Chengjun, Zuo, Jian-Min, Yang, Hong
• Format: Article
• Language: English
• Subjects: Atomically dispersed; Dual-ligated; ENGINEERING; Immobilized; Non-platinum group metal; Oxygen reduction reaction; Single atom
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2021.106547

This paper describes the use of both atomically dispersed precursors (ADPs) and conductive carbon dispersion towards the synthesis of iron-based single atom electrocatalysts for the oxygen reduction reaction (ORR). For non-platinum group metal (non-PGM) catalysts, single iron, cobalt or manganese atoms coordinated with nitrogen are the most active structures towards the ORR. Achieving a high density of active sites made of single atoms is still challenging, requiring careful controls of pyrolysis to reduce the sintering of metal active sites. Herewith, we present a new strategy to synthesize iron-based single atom ORR electrocatalysts using a two-pronged approach. We first designed a dual-ligated metal organic framework (MOF) precursor. This MOF was then immobilized onto Ketjen black carbon that serves as a conductive dispersion medium for creating the highly dispersed single atom sites. We demonstrate a near complete dispersion of the iron sites without obvious formation of nanoparticles. The activity of the resulting electrocatalyst exhibited an onset potential of 0.96 V and a half-wave potential of 0.84 V vs. reversible hydrogen electrode (RHE). [Display omitted] •Single atom oxygen reduction reaction electrocatalysts were synthesized from bidentate ligated metal organic frameworks.•Dual-ligand approach facilitated the control of distance between single atoms for high density distribution of active sites.•Immobilizationon conductive carbon improved the dispersion of single atoms and the formation of dispersed metal ion centers.•Single Fe atom catalyst has a high ORR activity with an onset potential of 0.96 V and a half-wave potential of 0.84 V in acid.