Oxygen Electroreduction on Nanoporous Carbons: Textural Features vs Nitrogen and Boron Catalytic Centers. Issue 2 (9th January 2019) - Florent, Marc
Abstract: Porous carbons containing either B and N heteroatom (∼10 at.% each) or B‐ and N‐free were synthesized and used as ORR metal‐free catalysts. The number of electron transfer was close to 4 (3.94) regardless the presence or not of heteroatom‐based catalytic centers, and the onset potential reached 0.827 V (on Pt/C 0.888 V). The carbons were extensively characterized from the viewpoints of their surface chemistry and porosity. The results indicated that a high volume of small pores where oxygen can be strongly adsorbed enhances the ORR efficiency, positively affecting the number of electron transfer and the value of the onset potential. On carbons with moderate volume of ultramicropores, N and B catalytic centers compensate the porosity effect enhancing the performance. These two mechanisms of ORR can coexist leading to a very efficient process on metal free carbon‐based porous catalysts. Abstract : Doping versus porosity : A comparative study of oxygen reduction reaction on nanoporous carbons containing or free of B and N heteroatoms was conducted. The adjustment of the porosity toward the formation of ultramicropores can be sufficient to attain a high catalytic efficiency. N and B catalytic centers were found as compensating a moderate volume of ultramicropores, resulting in well‐performing catalysts.