Potassium associated manganese vacancy in birnessite-type manganese dioxide for airborne formaldehyde oxidation

Abstract

The relationship between K+ and Mn vacancies and the significant effect of the K+ content on the structure, morphology and catalytic activity of birnessite-type MnO2 for HCHO oxidation was systematically studied.

Progress of Catalytic Oxidation of Formaldehyde over Manganese Oxides

“…However, there exists an optimal K + content in MnO 2 for the improvement of catalytic activity in HCHO oxidation according to the Rong's results of experiments and DFT theoretical calculation . In the low K + content range, increasing the content of K + will greatly improve the lattice oxygen activity and therefore increase the catalytic activity of HCHO oxidation.…”

“…There isn't a consistent understanding about the reaction mechanisms of HCHO oxidation over manganese oxide catalysts, and the studies on mechanism in the literature are rare, and further investigations about the mechanism are necessary. In particular, more attention should be paid on the relation of the surface properties of these catalysts with catalytic performance, the specific role of surface oxygen species and alkali metal (Na + , K + ) . These studies will further deepen the understanding of catalytic oxidation of formaldehyde over manganese oxides and lay a theoretical foundation for further development of more efficient and low‐cost manganese oxide catalysts.…”

Electrochemical performance of nanosized MnO2 synthesized by redox route using biological reducing agents

“…This is consistent with the assumption that Li + motion requires a stable tunnel framework, which is ensured by the presence of larger cations such as K + . It is well known that Li + ions are located on off-center 8h and 8h' Wyckoff positions (near the walls of the 2×2 tunnels) and the presence of K + ions on the centered 4e sites affects the electrochemical features and the overall discharge capacity [45]. Fig.…”

“…We pay a special attention to characterize the crystal chemistry of α-type MnO2 prepared from redox reaction of potassium permanganate, which always contains a residual fraction of K + ions in the 2×2 tunnels preserving the structural stability of this material. Note that most of numerous works published in the literature neglect this aspect; only few papers consider the presence of potassium in the cryptomelane framework [44][45][46][47][48][49][50][51]. Two samples were prepared using a redox synthesis…”

Facile preparation, characterization, and formaldehyde elimination performance of MnOx/natural loofah composites

“…46 The peaks of MnO x here appeared to be weak and broad due to amorphous phase and poor crystallinity of species. 51 The peak at 1,131 cm −1 was caused by bending vibration (δ[CH 2 ]) of methylenedioxy. 46 The weak peak at 1,740 cm −1 was assigned to ν(C=O) of carbonate species.…”