Investigation into the Phase–Activity Relationship of MnO₂ Nanomaterials toward Ozone‐Assisted Catalytic Oxidation of Toluene

Abstract

Manganese dioxide (MnO2), with naturally abundant crystal phases, is one of the most active candidates for toluene degradation. However, it remains ambiguous and controversial of the phase–activity relationship and the origin of the catalytic activity of these multiphase MnO2. In this study, six types of MnO2 with crystal phases corresponding to α‐, β‐, γ‐, ε‐, λ‐, and δ‐MnO2 are prepared, and their catalytic activity toward ozone‐assisted catalytic oxidation of toluene at room temperature are studied, which follow the order of δ‐MnO2 > α‐MnO2 > ε‐MnO2 > γ‐MnO2 > λ‐MnO2 > β‐MnO2. Further investigation of the specific oxygen species with the toluene oxidation activity indicates that high catalytic activity of MnO2 is originated from the rich oxygen vacancy and the strong mobility of oxygen species. This work illustrates the important role of crystal phase in determining the oxygen vacancies’ density and the mobility of oxygen species, thus influencing the catalytic activity of MnO2 catalysts, which sheds light on strategies of rational design and synthesis of multiphase MnO2 catalysts for volatile organic pollutants’ (VOCs) degradation.

Catalytic Oxidation of NO over Fe-Doped MnO2 Catalyst

“…Table S2 lists the content of each Mn species in each catalyst, and the proportion of low-valence Mn (Mn 2+ and Mn 3+ ) follows the order: Fe-MnO 2 -5 (69.7%) > Fe-MnO 2 -7 (65.0%) > Fe-MnO 2 -3 (63.1%) > MnO 2 (62.7%). Notably, the order of low-valence Mn content agrees well with the order of O ads content in catalyst, resulting from the fact that the proportion of low-valence Mn in catalyst is an indicator of SOVs on catalyst surface, , while O ads originates from the adsorption of O 2 on SOVs …”

Enhanced cathode integrity for zinc–manganese oxide fiber batteries by a durable protective layer

“…44-0992) except for a peak located at 25.5 coming from CNTs in the current collector. 25 This result conrmed that the introduction of a multifunctional protective layer had little effect on the structure of electrodeposited MnO 2 .…”

Exploiting the synergistic effect of multiphase MnO2 stabilized by an integrated conducting network for aqueous zinc-ion batteries

“…S3 and S4, ESI †), respectively. 26 However, no specific ring/lattice pattern of PEDOT is observed, indicating that PEDOT is an amorphous structure. Energy-dispersive spectroscopy mappings of C, S, Mn and O elements further verify the uniform synthesis of the material and the successful cladding of the PEDOT molecule, confirming the formation of an integrated conductive structure of DMOP (Fig.…”