Evolution of oxygen vacancies in MnOx-CeO2 mixed oxides for soot oxidation

Lin, Xueting; Li, Shujun; He, Hui; Wu, Zhuangchun; Wu, Junliang; Chen, Limin; Ye, Daiqi; Fu, Mingli

doi:10.1016/j.apcatb.2017.06.071

Cited by 428 publications

(130 citation statements)

References 59 publications

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“…Table 2 Figure 4 shows the N 2 adsorption-desorption isotherms. All samples have typical type IV isotherm showing a hysteresis loop at high relative pressures, which is associated with capillary condensation representative of mesoporous materials [24][25][26][27][28]. This is confirmed by the mean pore size shown in Table 2, where all samples have a pore size in the range of mesopores (2-50 nm).…”

Section: Resultssupporting

confidence: 66%

“…The adsorbed oxygen starts to reacts with soot at temperatures below 500 • C, and an increment in the mass loss, attributed to the soot combustion, is clearly detected. In contrast, the preservation of the perovskite structure with high Mn 3+ content in Mn1 and Mn4, which correlates with the formation of surface oxygen vacancies, can produce a competing oxidation reaction between soot combustion and the oxidation of Mn 3+ to Mn 4+ , resulting in rapidly filled surface oxygen vacancies and low mass loss (see Figure 5c), as described by Xueting et al [27]. However, at temperatures higher than 500 • C, oxygen migrates from the bulk to the catalyst surface.…”

Section: Resultsmentioning

confidence: 92%

“…By increasing the temperature, oxygen migrates from the bulk to the surface, enhanced by the redox pair Mn 3+ /Mn 4+ and the existence of Ti 3+ /Ti 4+ species (Red arrow in Figure 6). Mn1, with high Mn 3+ content and oxygen vacancies, can transport oxygen from the bulk to the surface and enhance the soot oxidation rate (Green arrow in Figure 6) [13,27]. Another possibility causing the behavior observed in Figure 5c is the better dispersion of Mn species on the surface of Mn1 and Mn4 catalysts against Mn8.…”

Section: Resultsmentioning

confidence: 94%

“…The deconvolution analysis shows two well defined peaks in all samples located at 528.8 and 530.6 eV, which are respectively attributed to lattice oxygen (Olat) from the perovskite structure or surface segregated oxides and surface adsorbed oxygen (Oads), associated with defect oxides [27], carbonates or hydroxyl species, as well as weakly bonded oxygen adsorbed on the surface [13,26]. The Oads/Olat ratio shown in Table 2 demonstrates high Oads in the Mn1 sample, which can be attributed to the structural defects produced by the Mn 3+ /Mn 4+ ratio shown in Table 2 [1].…”

Section: Resultsmentioning

confidence: 99%

“…However, at temperatures higher than 500 • C, oxygen migrates from the bulk to the catalyst surface. The Mn1 sample, rich in structural defects (as shown in Figure 3b), is the best catalyst for oxygen transportation via the ion-mobility mechanism [13,27], which promotes the combustion of soot. Mass loss increases dramatically as a consequence.…”

Section: Resultsmentioning

confidence: 99%

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Effect of Dopant Loading on the Structural and Catalytic Properties of Mn-Doped SrTiO3 Catalysts for Catalytic Soot Combustion

et al. 2018

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Soot particles have been associated with respiratory diseases and cancer. To decrease these emissions, perovskite-mixed oxides have been proposed due to their thermal stability and redox surface properties. In this work, SrTiO 3 doped with different amounts of Mn were synthesized by the hydrothermal method and tested for soot combustion. Results show that at low Mn content, structural distortion, and higher O ads /O lat ratio were observed which was attributed to the high content of Mn 3+ in Ti sites. On the other hand, increasing the Mn content led to surface segregation of manganese oxide. All synthesized catalysts showed mesopores in the range of 32-47 nm. In the catalytic combustion of soot, the samples synthesized in this work lowered the combustion temperature by more than 100 • C compared with the uncatalyzed reaction. The sample doped with 1 wt % of Mn showed the best catalytic activity. The activation energy of these samples was also calculated, and the order of decreasing activation energy is as follows: uncatalyzed > Mn0 > Mn8 > Mn4 > Mn1. The best catalytic activity for Mn1 was attributed to its physicochemical properties and the mobility of the oxygen from the bulk to the surface at temperatures higher than 500 • C.

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Section: Resultssupporting

confidence: 66%

Section: Resultsmentioning

confidence: 92%

Section: Resultsmentioning

confidence: 94%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 3 more Smart Citations

Effect of Dopant Loading on the Structural and Catalytic Properties of Mn-Doped SrTiO3 Catalysts for Catalytic Soot Combustion

et al. 2018

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Oxygen Vacancies‐Rich Metal Oxide for Electrocatalytic Nitrogen Cycle

Wei,

Chen,

et al. 2023

Advanced Energy Materials

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The development of industry and agriculture has been accompanied by an artificially imbalanced nitrogen cycle, which threatens human health and ecological environments. Electrocatalytic systems have emerged as a sustainable way of converting nitrogen‐containing molecules into high value‐added chemicals. However, the construction of high‐performance electrocatalysts remains challenging. The development of oxygen vacancy engineering strategy has promoted more research efforts to explore the structure‐activity relationship between catalytic activity and oxygen vacancies. This review systematically summarizes the recent development of oxygen vacancies‐rich metal oxides for electro‐catalyzing nitrogen cycling systems, involving electrocatalytic nitrate reduction reaction, nitric oxide reduction reaction, nitrogen reduction reaction, C─N coupling, urea oxidation reaction, and nitrogen oxidation reaction. First, the construction methods and characterization methods of oxygen vacancies are summarized. Then, the effect of oxygen vacancy on electrocatalytic activity of metal oxides is discussed in terms of regulating the electronic structures of electrocatalysts, improving the electroconductivity of catalysts, lowing the energy barrier, and strengthening adsorption and activation of intermediate species. Finally, future directions for oxygen vacancy engineering and electrocatalytic nitrogen cycle are anticipated.

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