Elucidating structure-performance correlations in gas-phase selective ethanol oxidation and CO oxidation over metal-doped γ-MnO2

Recent progresses in the synthesis of MnO2 nanowire and its application in environmental catalysis

“…As for γ-MnO 2 , Zn-doped MnO 2 could achieve the 90% CO conversion at 160 °C and perform the best CO oxidation activity among Cu, Zn, Mg, Co, Ni, Ca, Al, Fe, and La-doped γ-MnO 2 . 128 Besides, the surface engineering is considered as another effective method to improve the catalytic activity of MnO 2 . Li et al 92 synthesized α-MnO 2 with a large number of surface open cells through acid treatment.…”

Exploring the roles of oxygen species in H2 oxidation at β-MnO2 surfaces using operando DRIFTS-MS

“…Some success has been achieved via doping with secondary metal ions and nano structuring 14 , 15 , and the doping strategy has been expanded to develop four-layer metal oxide catalysts (CuO/VO x /Ti 0.5 Sn 0.5 O 2 ) with layers composed of synergistic OV concentrations 16 . The dispersal of metal ions on the surfaces of metal oxides has also been demonstrated to increase the concentration of OVs effectively 17 , 18 . These strategies have been widely used in photocatalytic materials, electrocatalytic materials, thermal catalytic materials, and optical materials 19 – 21 .…”

Effect of MnO2 Polymorphs’ Structure on Low-Temperature Catalytic Oxidation: Crystalline Controlled Oxygen Vacancy Formation

“…The pyrolusite-type β-MnO 2 ( P 42/ mnm ) has a rutile-type structure with infinite [MnO 6 ] octahedral chains that share opposing edges. Each chain is connected with four similar chain corners, leading to the formation of (1 × 1) tunnels in this structure. − The structural feature of γ-MnO 2 is the random intergrowth of ramsdellite-type (1 × 2 tunnels) and pyrolusite (1 × 1 tunnels) matrices, where the basic building blocks of [MnO 6 ] octahedra share the corners and edges. , The structure of birnessite-type δ-MnO 2 consists of [MnO 6 ] octahedral sheets that share edges, forming a two-dimensional (2D) layer structure with the interlayers filled with K + OH – or H 2 O. , The structure of akhtenskite-type ε-MnO 2 is a polymorph of MnO 2 with a hexagonal symmetry, first discovered by De Wolff et al It exhibits a NiAs-type structure with half cationʼs vacancies and Mn 4+ randomly distributed. , However, the ordered structure of ε-MnO 2 and the DFT calculations have also been proposed and performed in recent years, respectively. − Hong and co-authors revealed a ε-MnO 2 material by acid leaching of LiMnO x . The formation energies of oxygen vacancies were calculated based on both bulk and surface ε-MnO 2 by DFT calculations .…”

“…11−14 The structural feature of γ-MnO 2 is the random intergrowth of ramsdellite-type (1 × 2 tunnels) and pyrolusite (1 × 1 tunnels) matrices, where the basic building blocks of [MnO 6 ] octahedra share the corners and edges. 15,16 The structure of birnessite-type δ-MnO 2 consists of [MnO 6 ] octahedral sheets that share edges, forming a twodimensional (2D) layer structure with the interlayers filled with K + OH − or H 2 O. 17,18 The structure of akhtenskite-type ε- MnO 2 is a polymorph of MnO 2 with a hexagonal symmetry, first discovered by De Wolff et al 19 It exhibits a NiAs-type structure with half cationʼs vacancies and Mn 4+ randomly distributed.…”