Sn modulated Co-NC catalysts with enriched active sites boost oxygen reduction reaction.

Introducing the second metal is an effective strategy to ameliorate oxygen reduction reaction (ORR) performance of cobalt and nitrogen doped carbon materials (Co-NC). In this study, Sn modulated Co-NC catalysts with enriched active sites (CoSn-NC) were synthesized by using formamide as ligand. Co and Sn bimetals coexist on nitrogen-doped carbon carriers and coordinated with nitrogen to form M − N active centers. Compared with Co-NC, CoSn -NC exhibited outstanding catalytic activity in terms of early initial potential of 1.04 V and positive half-wave potential of 0.89 V. Electrochemical testing and XPS characterization proved that the addition of Sn enriched the active site of Co-NC. More importantly, the electronic structure of Co–N is adjusted to perfect adsorption energy of the intermediate. The study puts forward a new idea and direction for optimizing single metal Co-NC catalyst. Synopsis: This paper is committed to developing Cobalt-based bimetallic materials with enrich active sites to replace scarce Pt/C for ORR. [Display omitted] • Co and Sn bimetals coexist on nitrogen-doped carbon carriers. • Sn Modulated Co-NC catalysts with enriched active sites. • The M − N structure is the main catalytic site by SCN− toxicity experiments. • CoSn-NC shows enhanced ORR catalytic activity, stability and methanol resistance. [ABSTRACT FROM AUTHOR]