Pyrazinium Ionic Liquid for Preparing A 0D/2D Hybridized N, P-codoped Carbon Enriched with Pyridinic N and Enhanced Electrocatalytic Performance toward Oxygen Reduction Reaction

Abstract

For the low volatility, heteroatom-rich composition, ionic liquids (ILs) are considered as excellent precursors for various porous heteroatom-modified carbon materials, which exhibit good electrocatalytic activity for the oxygen reduction reaction (ORR). In the heteroatommodified carbons, the pyridinic N-doped carbon is considered the active sites. Herein, the pyrazine IL that structurally resembles the pyridinic N-doped carbon is selected as the precursor for a N, P co-doped carbon (C pyr ), which exhibits a high pyridinic N content of 19.2 at. %. The controlling sample (C mim ) derived from the 2-methylimidazole only possesses a pyridinic N content of 11.2 at.%. Meanwhile, the pyrazine IL-derived C pyr has an unique 0D/2D hybridized morphology and a larger electrochemical surface area, while the C mim displays the general sheet-like disappearance. The high pyridinic N content and unique 0D/2D hybridized structure synergistically enhances the ORR performance of C pyr . The onset potential and half-wave potential of the C pyr respectively arrive 0.94 V RHE and 0.75 V RHE , while that of C mim are 0.90 V RHE and 0.58 V RHE . Consequently, this work provides an inspirational strategy to prepare the highly electroactive carbon materials via rationally designing the IL precursor at the molecular level.