Multiple Metal (Cu, Mn, Fe) Centered Species Simultaneously Combined Nitrogen‐doped Graphene as an Electrocatalyst for Oxygen Reduction in Alkaline and Neutral Solutions

Abstract

A new efficient composite catalyst (CuIMnFeIIIO/NG) for oxygen reduction reaction (ORR) in both alkaline and neutral media, is successfully prepared via a facile, clean, low‐cost and reproducible solvothermal method without any further treatments. The nanoparticles consisting of crystalline phases of Fe2O3, MnCO3 and amorphous Cu2O&MnxOy (CuIMnO), are anchored on nitrogen‐doping graphene (N/C atomic ratio up to 10.56 %), which offer various active sites toward ORR. The synergistic catalytic effect between these components affords excellent ORR performance with comparable onset potential and current density to commercial Pt/C in both pH‐situations, and a 4‐electron‐transfer path during oxygen reduction. Furthermore, comparative experiment results are discussed to describe the different degrees of ORR contribution in different medium from metal species and nitrogen doping. Meanwhile, superior methanol tolerance and high stability of CuIMnFeIIIO/NG can make it a promising alternative for expensive commercial Pt‐based electrocatalysts in corresponding alkaline and neutral fuel cells.

Mn3+ Active Surface Site Enriched Manganese Phosphate Nano‐polyhedrons for Enhanced Bifunctional Oxygen Electrocatalyst

“…The surface binding state and elemental composition analysed from the XPS analysis is shown in Figure . The Mn 2p core‐level spectra were deconvoluted into two major peaks such as Mn 3+ (641.8 eV) and Mn 4+ (643.5 eV) . It is highly anticipated that the higher Mn 3+ content would be highly reactive to oxygen reduction and increase the OH− adsorption.…”

Construction of Cu2+-doped MnCO3 micro-rhombohedrons and micro-olives as promising anode materials for high performance lithium-ion batteries

“…15 On the other hand, part of Mn 2+ and Cu 2+ chelated with the NH 3 molecules, resulting in the formation of [Mn(NH 3 ) n ] 2+ and [Cu(NH 3 ) n ] 2+ . 16,17 According to the report of Garcia et al, the rhombohedral MnCO 3 particles tend to be formed at lower Mn 2+ concentration, while the spherical MnCO 3 can be prepared at a higher Mn 2+ concentration. 16 As the amount of Cu(NO 3 ) 2 •3H 2 O increased, more copper-ammonia complexes will be formed, which means that more Mn 2+ can be released from the manganese-ammonia complexes, resulting in a significant increase in Mn 2+ concentration in the reaction system, and thus the formed MnCO 3 particles become olive-shaped.…”

Mn3P2O8/TiN on Titanium Substrate for Superapacitor Electrode with Long Cycle Stability in KOH and Na2SO4 Aqueous Eletrolytes

“…A broad peak for Mn 2p 3/2 spectra shown in Fig. 4c is deconvoluted into four binding energy regions, which of two overlapping major peaks at 641.02 eV and 642.25 eV are attributed Journal of The Electrochemical Society, 2022 169 110520 to Mn 2+ and Mn 3+ respectively, 22 and binding energy regions at 645.08 and 647.28 eV are shake up peaks caused by it. 23,24 The P 2p 3/2 and 2p 1/2 peaks are observed at 132.5 eV and 133.3 eV in Fig.…”