Modulating the electrocatalytic activity of N-doped carbon frameworks via coupling with dual metals for Zn–air batteries

Abstract

N-Doped carbon electrocatalysts are a promising alternative to precious metal catalysts to promote oxygen reduction reaction (ORR). However, it remains a challenge to design the desired active sites on carbon skeletons in a controllable manner for ORR. Herein, we developed a facile approach based on oxygen-mediated solvothermal radical reaction (OSRR) for preparation of N-doped carbon electrocatalysts with a pre-designed active site and modulated catalytic activity for ORR. In the OSRR, 2-methylimidazole reacted with Co and Mn salts to form an active site precursor (MnCo-MIm) in N-methyl-2-pyrrolidone (NMP) at room temperature. Then, the reaction temperature increased to 140 °C under an oxygen atmosphere to generate NMP radicals, followed by their polymerization with the pre-formed MnCo-MIm to produce Mn-coupled Co nanoparticle-embedded N-doped carbon framework (MnCo-NCF). The MnCo-NCF showed uniform dispersion of nitrogen atoms and Mn-doped Co nanoparticles on the carbon skeleton with micropores and mesopores. The MnCo-NCF exhibited higher electrocatalytic activity for ORR than did a Co nanoparticle only-incorporated carbon framework due to the improved charge transfer from the Mn-doped Co nanoparticles to the carbon skeleton. In addition, the Zn–air battery assembled with MnCo-NCF had superior performance and durability to the battery using commercial Pt/C. This facile approach can be extended for designing carbon electrocatalysts with desired active sites to promote specific reactions. Graphical Abstract

Mn-doped Co nanoparticles on wood-derived monolithic carbon for rechargeable zinc–air batteries

“…The coupling of weak electronegative Mn changes Co nanoparticles into electron-rich active sites with enhanced electrocatalytic activity. 41 The Mn–N site is justified by the Mn 2p 3/2 (641.4 eV) and Mn 2p 1/2 (653.5 eV) peaks, together with two satellite peaks at 644.9 and 659.1 eV (Fig. 3f).…”

Hierarchical Porous Carbon with N/S Codoped Bimetal as a High-Efficiency Oxygen Reduction Catalyst for Rechargeable Zinc–Air Batteries

“…In the zinc–air battery, the oxidation–reduction reaction, which occurs on the cathode, is the core process by the gain and loss of electrons to produce current. However, ORR suffers high activation energy and slow kinetics, and effective electrocatalysts are required to accelerate it . Platinum (Pt)-based electrocatalysts, such as Pt/C catalyst, can effectively reduce the ORR activity and have been widely used in accelerating the ORR process.…”

“…However, ORR suffers high activation energy and slow kinetics, and effective electrocatalysts are required to accelerate it. 11 Platinum (Pt)-based electrocatalysts, such as Pt/C catalyst, can effectively reduce the ORR activity and have been widely used in accelerating the ORR process. Unfortunately, natural scarcity, high cost, and poor stability of Pt-based materials limit their widespread application.…”

MOF-Based Co and Mn Embedded in Nitrogen-Doped Microporous Carbon as an Efficient Catalyst for Oxygen Reduction Reaction in Anion Exchange Membrane Fuel Cell

“…Chen et al [32] calcined MnO 2 hollow nanowires@ZIF-67 to generate highly porous MnO@Co-N/C and showed the half-wave potential of 0.83 V in 0.1 M KOH. Park et al [35] first produce a precursor (MnCo-MIm) by mixing Co and Mn salts with 2-methylimidazole in N-methyl-2-pyrrolidone (NMP). MnCo-NCF was synthesized by pyrolyzing MnCo-MIm and exhibited the halfwave potential of 0.843 V in 0.1 M KOH.…”