Inverse Coprecipitation Directed Porous Core–Shell Mn–Co–O Catalyst for Efficient Low Temperature Propane Oxidation

Abstract

Mn–Co–O catalysts with different Mn/Co molar ratios were synthesized by means of a facile inverse coprecipitation strategy and applied for the oxidation of propane (C3H8). The XRD pattern of Co2Mn1Oδ (molar ratio of Mn:Co = 1:2) indicates a Co3O4 phase, and most Mn incorporates into Co3O4 lattice to form a solid solution. Minor distributed Mn species occur structure reforming, totally converting to a stable Co–Mn solid solution during oxidation process. Meanwhile, Co2Mn1Oδ features a porous core–shell morphology, the core and shell of which are made up of Co–Mn solid solution, giving rise to a high surface area. The optimized synergistic effect of manganese and cobalt improves low temperature reducibility and produces rich surface active Co3+ species and surface-absorbed oxygen over Co2Mn1Oδ. As a result, it exhibits a prominent excellent catalytic activity, and delivers good thermal stability in the presence of 5 vol % H2O and 5 vol % CO2. In situ DRIFTs analysis displays the reaction path of C3H8 over Co2Mn1Oδ, where dominate intermediate species formate are easily decomposed into CO2. The synthesized porous core–shell Mn–Co–O can be a promising candidate replacing non-noble catalysts toward C3H8 oxidation at low temperature.

Mn-doped Co3O4 for acid, neutral and alkaline electrocatalytic oxygen evolution reaction

“…A similar mixture of MnO x and CoO x phases was also described for Mn-Co-O catalysts with different Mn/Co molar ratios. 17,29 A thorough analysis of the samples containing Co 3 O 4 revealed that there was a shi to lower values of 2q with the increase of Mn : Co molar ratio, indicating an increase of the lattice cell parameters (Table S1 †), similar effect has been described in previous works. 30,31 For instance, the lattice parameter a is 8.09 nm in the sample Co 3 O 4 and increased accordingly to 8.11, 8.12, and 8.13 nm in Mn@Co 3 O 4 -1, Mn@Co 3 O 4 -2, and Mn@Co 3 O 4 -3, respectively.…”

“…A similar mixture of MnO x and CoO x phases was also described for Mn–Co–O catalysts with different Mn/Co molar ratios. 17,29…”

“…The development of highly efficient OER electrocatalysts under neutral and acid conditions is very important for safe and low-cost water splitting electrolyzer. 4,29 In respect to the Co and Mn content, the catalysts with higher weight percentage of Co 3 O 4 phase showed the highest activities in all pHs. Fig.…”

Facet-Dependent Mn Doping on Shaped Co3O4 Crystals for Catalytic Oxidation

“…Doping other transition metals into Co 3 O 4 has been extensively studied to improve catalytic activity. − The metal dopant can affect the surface oxygen property by changing the geometric and electronic properties of the host metal oxide. For example, In doping changed the chemical states of chemisorbed oxygen on Co 3 O 4 surfaces, improving the surface oxygen mobility, resulting in promoted activity for CO oxidation. , Also, Ni doping into Co 3 O 4 could enhance the catalytic activity for propane oxidation. , In particular, Mn has been considered to significantly improve the activity of Co 3 O 4 for various catalytic oxidations. − The Mn doping could generate more active oxygen species on the Co 3 O 4 surface, resulting in improved activity. − The strong interaction between Mn and Co also improved the structural stability of the catalyst surface. , However, depending on the surface structures of Co 3 O 4 , the specific coordinations between Co and O were different, affecting the surface oxygen properties. − The effect of metal doping depending on the surface structure has not been clearly revealed. We hypothesized that the doping feature would vary for different surface structures of Co 3 O 4 .…”

Electroplating Sludge-Derived Multiple-Metal-Doped Spinel with Superior CO Selectivity in Reverse Water–Gas-Shift Reaction

“…According to the elemental components (Table ) and diffraction peaks (Figure ) of the derived catalysts, reduction peaks of ZnCr-2 and ZnCr-3 were shifted to lower temperatures with the increase in Cu and Zn contents. Reduction peaks derived from Mn and Ni were distributed at 300–500 °C. , If the peak belonged to Ni, it was a large-particle bulk NiO, which was weakly linked to the carrier (such as ZnCr-1). Otherwise, the peak was the reduction of Mn 3+ to Mn 2+ (such as ZnCr-2 and ZnCr-3).…”