Stimulation of electrocatalytic oxygen reduction activity on nitrogen doped graphene through noncovalent molecular functionalisation

Abstract

Molecular doping on graphene, through noncovalent functionalization offers a great opportunity to tune charge density on graphene for catalytic applications. Although enhanced oxygen reduction activity has been reported in heteroatom doped graphene, the synergistic advantage of molecular and heteroatom co-doping has not yet been studied. Here, we report the remarkably enhanced catalytic activity of benzoate or 1-pyrenebutyrate functionalized N-doped graphene (BA-NrGO/PB-NrGO) towards the oxygen reduction reaction (ORR) in alkaline medium. An efficient 4e⁻ reduction process with a more positive onset potential (E_onset = 0.85 V vs. RHE) and high ORR activity (J_k = 3.16 mA cm⁻² at 0.65 V) has been observed in BA-NrGO. DFT studies show that the stimulated ORR activity is due to functionalisation induced increased charge density on active sites.