<br/>Oxygen reduction reaction (ORR) is critical for metal-air battery and polymer membrane-based fuel cell technologies. Considerable effort has been expended to develop inexpensive, highly active, and durable electrocatalysts to replace the scarce and expensive Pt which is prone to poisoning during ORR. However, limited progress in a fundamental understanding of catalytic mechanisms has been made in part due to a lack of means to obtain the structure-activity relationship.<br/>We herein describe a new synthetic strategy that enables the formation of a hierarchical structure, composed of a thin d- and p-block transition metal coordinated polymeric layer, poly (4-vinylpyridine)(P4VP) which is grafted on a carbon surface. Pyridinic groups in P4VP can absorb metal species via either coordination or electrostatic interaction. Therefore the type and size of catalyst – metal coordinated N-doped carbon – can be engineered by types and amounts of metal precursors. This system that can keep all other parameters such as catalyst spatial distribution and electrical connectivity to their support the same enables a fair comparison between catalytic activity for establishing a correlation of catalyst property and ORR performance. The impact of the morphology of carbon support on current density will be also discussed.<br/>We chose noble-metal-free and Fe-free catalyst systems because of the potential in favor of the four-electron oxygen reduction pathway and Fenton-inactive character. We revealed the effect of ligand types and Sn oxidation states on the properties of metal-pyridine complexes using Fourier Transform Infrared Spectroscopy (FTIR), thermogravimetric analyzer (TGA), and consequent catalyst composition by X-ray Photoelectron spectroscopy XPS). Using our newly constructed hierarchical platform, the effect of Sn-based catalyst precursor composition on ORR activity is set forth.

Single atom Sn-N coordinated ORR catalysts by using sacrificing polymer substrate

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.