Understanding the crucial role of local crystal order in the electrocatalytic activity of crystalline manganese oxide

Abstract

In situ spectroscopic investigation elucidates the crucial role of local structural order in the excellent electrocatalytic activity of crystalline MnO2.

Manganese-based oxide electrocatalysts for the oxygen evolution reaction: a review

“…To explore efficient MnO x electrocatalysts, it is essential to clarify the dominant factors controlling the electrocatalytic activity of these oxides. 92 Above we have comprehensively reviewed the progress of MnO 2 , Mn 3 O 4 , and Mn 2 O 3 materials, many of which have encountered several common problems such as Jahn-Teller distortion, active sites, stability, etc. These critical issues have hindered the understanding of catalytic reaction mechanisms and the development of efficient and stable catalysts.…”

Development of α‐MnO2 Nanowire with Ni‐ and (Ni, Co)‐Cation Doping as an Efficient Bifunctional Oxygen Evolution and Oxygen Reduction Reaction Catalyst

“…Further, doping of metal atoms with α-MnO 2 is an efficient strategy for tailoring the oxygen defects, surface sites, valence of Mn and electron transfer ability. Lee et al, [34] suggested that the Fe substitution in α-MnO 2 causes significant enhancement in the structural order of MnO 6 octahedral which showed remarkable charge transfer performance. Single/co-doping of metal ions, especially Ni, and Co into α-MnO 2 matrix has proven one of the excellent ways to improve the bifunctional activity towards OER and ORR.…”

Operando XAS of a Bifunctional Gas Diffusion Electrode for Zn-Air Batteries under Realistic Application Conditions

“…It can be noticed that the FT signal remained relatively unchanged when comparing the ORR and the OER processes, where only the second peak (Mn-Mn edge ) shows a small increase under the OER process. Such a weak rise in intensity of the FT peak may be attributed to the formation of additional bonds in the defective manganese oxide lattice [3] or to the depression of local structural disorder [13]. According to Lee et al [13], FT peak enhancement during the OER process can be regarded as clear evidence of the improved collinear alignment of the MnO 6 octahedra array.…”

“…Such a weak rise in intensity of the FT peak may be attributed to the formation of additional bonds in the defective manganese oxide lattice [3] or to the depression of local structural disorder [13]. According to Lee et al [13], FT peak enhancement during the OER process can be regarded as clear evidence of the improved collinear alignment of the MnO 6 octahedra array. The shape and intensity of the FT peaks change drastically after the partial O 2 starvation process.…”

“…The second Mn-O interaction (Mn-O ads ) considers possible adsorbed oxygen-containing species (for instance, intercalated water molecules) [14], as well as hydroxide end groups on the catalyst surface [15]. The last two interactions are associated with the interatomic distances Mn-Mn edge and Mn-Mn corner [13,16]. Systematic variation of the choice and combination of scattering path showed that neglecting one of the Mn-Mn or Mn-O paths leads to a degradation of the fit quality; in particular, subtle, but diagnostic details of the crypomelane structure cannot be followed.…”