Construction of a Co/MnO Mott–Schottky Heterostructure to Achieve Interfacial Synergy in the Oxygen Reduction Reaction for Aluminum–Air Batteries

Abstract

The rational design of non-noble metal-based electrocatalysts for an efficient oxygen reduction reaction (ORR) is an important research topic to promote the advancement of aluminum−air batteries. In this work, heterostructural Co/MnO nanoparticles encapsulated in a N-doped carbon electrocatalyst were prepared via one-step pyrolysis utilizing different reduction potentials of Co and Mn ions, and the heterointerface between the two phases was confirmed. The prepared catalyst displays Pt/C competitive ORR performance because of the interfacial synergy of a Co/MnO Mott−Schottky (M−S) heterostructure, which leads to boosted conductivity, formation of an M−S barrier, and a reduced oxygen reduction energy barrier for excited electrons. Furthermore, the Co/MnO-based aluminum−air battery displays good discharge performance, demonstrating good feasibility for practical application.

Construction of core‐shell heterostructured MnO@Co/NC for enhancing the oxygen electrocatalytic performance

“…To accomplish the uniform coating, the MnO 2 nanotubes underwent functionalization with anionic surfactant sodium dodecyl sulfate to facilitate the adsorption of positively charged Co 2+ , which enabled dopamine to easily form a polydopamine outer layer. Within the PDA, the groups containing O− and N− supply lone pairs to fill the vacant electron orbits of Co 2+ , realizing a uniform anchoring of the metal ions within the PDA [29] . As indicated in Figure S2, the dopamine peaks (1165 cm −1 and 875 cm −1 ) are discernible in the FTIR spectra of MnO 2 @Co/PDA, suggesting a successful encapsulation of polydopamine [30,31] .…”

“…Within the PDA, the groups containing OÀ and NÀ supply lone pairs to fill the vacant electron orbits of Co 2 + , realizing a uniform anchoring of the metal ions within the PDA. [29] As indicated in Figure S2, the dopamine peaks (1165 cm À 1 and 875 cm À 1 ) are discernible in the FTIR spectra of MnO 2 @Co/PDA, suggesting a successful encapsulation of polydopamine. [30,31] The ultimate core-shell heterostructured MnO@Co/NC nanotube was then obtained through pyrolysis of MnO 2 @Co/PDA as the precursor.…”

“…The doublet located at 787.2 eV and 803.5 eV can be attributed to the satellite peaks of Co 2p. The high ratio of ionic state for Co is predominantly influenced by the coordination of metallic Co with N and the generation of Co/MnO heterointerfaces with the Co−O bond [29] . Simultaneously, peaks at 641.0 eV and 652.5 eV can be assigned to Mn 2+ 2p 3/2 and Mn 2+ 2p 1/2 , originating from the MnO core (Figure 2f).…”

“…The high ratio of ionic state for Co is predominantly influenced by the coordination of metallic Co with N and the generation of Co/MnO heterointerfaces with the CoÀ O bond. [29] Simultaneously, peaks at 641.0 eV and 652.5 eV can be assigned to Mn 2 + 2p 3/2 and Mn 2 + 2p 1/2 , originating from the MnO core (Figure 2f). Besides, two peaks situated at 642.6 eV and 653.9 eV can be ascribed to Mn 4 + 2p 3/2 and Mn 2 + 2p 1/2 .This might be due to the mixed valence of Mn 2 + and Mn 4 + , which plays a crucial role in modifying the electronic structure and enhancing charge transfer.…”

Boosting oxygen reduction of well-dispersed CoP/V(PO3)3 sites via geometric and electronic engineering for flexible Zn–air batteries

“…Among these, the introduction of electron-rich compounds to form heterostructures can further optimize the density of state near Fermi level of the composites and promote the separation of positive and negative charges at the interface, which is considered as an efficient strategy to improve the electrochemical activity. 27,28 However, reported activities are at best modest (E 1/2 < 0.8 V vs. the reversible hydrogen electrode, RHE), generally far lower than those of Pt/C. 29,30 Furthermore, most reported materials suffer from a limited amount of active sites, immensely abating their ORR performance.…”