A comparative study of the catalytic oxidation of HCHO and CO over Mn0.75Co2.25O4 catalyst: The effect of moisture

Wang, Yu; Zhu, Xiaobing; Crocker, Mark; Chen, Bingbing; Shi, Chuan

doi:10.1016/j.apcatb.2014.06.011

Cited by 90 publications

(42 citation statements)

References 46 publications

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“…34 The bands at 1540 cm −1 are assigned to bicarbonate species and bidentate carbonate species. 35 For the K 2 CO 3 /Co 3 O 4 sample, the DOM accumulation of which was less, indicating that the oxidation rate was higher than for the other three samples. Also, the adsorption of carbon dioxide, water, bicarbonate and bidentate carbonate species was more than for the other three samples.…”

Section: In Situ Driftsmentioning

confidence: 83%

Promotion effect of potassium carbonate on catalytic activity of Co₃O₄ for formaldehyde removal

Fan

Shi

Zhang

et al. 2018

J of Chemical Tech & Biotech

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BACKGROUND: The effect of K 2 CO 3 on modified Co 3 O 4 was evaluated for the catalytic removal of formaldehyde (HCHO). The synthesized catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), BET surface area, H 2 temperature-programmed reduction (H 2 -TPR), CO 2 temperature-programmed desorption (CO 2 -TPD) and in situ diffuse reflectance infrared spectroscopy (DRIFTS) analyses. RESULTS: The results indicated that the Co 3 O 4 sample modified by 3 wt% K 2 CO 3 was able to provide 100% conversion of HCHOto CO 2 at 100 ∘ C, while KNO 3 and KCl could barely promote the catalytic performance of Co 3 O 4 . K 2 CO 3 increased the valence state of Co and the number of oxygen vacancies on the surface of modified Co 3 O 4 , thereby enhancing the oxidation ability. The product water on the Co 3 O 4 surface could convert the carbonate to bicarbonate via hydrolysis of K 2 CO 3 , which promoted hydroxyl regeneration and accelerated intermediate species oxidation. CONCLUSION: Thus, the Co 3 O 4 modified by an appropriate amount of K 2 CO 3 exhibited an excellent performance for formaldehyde oxidation removal. Catalytic activity of different anionic potassium salt loaded on Co 3 O 4Different potassium precursors were compared for the catalytic activity of K-promoted cobalt spinel for HCHO decomposition. The formaldehyde removal rate over the different anionic potassium salts that were loaded to the same potassium molar ratio of K 2 CO 3 /Co 3 O 4 (3 wt%) is shown in Fig. 2.The catalytic activity of KNO 3 /Co 3 O 4 and KCl/Co 3 O 4 was almost the same as the Co 3 O 4 catalyst. The temperature for 10% conversion rate of HCHO was 90 ∘ C and for complete conversion was 120 ∘ C for the three catalysts. Nevertheless, for K 2 CO 3 /Co 3 O 4 , the formaldehyde removal rate increased obviously at low

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Section: In Situ Driftsmentioning

confidence: 83%

Promotion effect of potassium carbonate on catalytic activity of Co₃O₄ for formaldehyde removal

Fan

Shi

Zhang

et al. 2018

J of Chemical Tech & Biotech

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“…As the water content increases in reaction feed gas, water may exhibit dual effects via blocking the surface active sites, one of which is decreasing the reaction activity . In the study of CO oxidation on Mn 0.75 Co 2.25 O 4 catalyst in humid air, Wang et al proposed three possible routes through which the active sites are gradually blocked by water: (1) water dissociative adsorption on oxygen vacancies; (2) water dissociative adsorption on metal cations; and (3) molecular adsorption of water on metal cations.…”

Section: Mechanistic Insightsmentioning

confidence: 99%

The promotional role of water in heterogeneous catalysis: mechanism insights from computational modeling

Chang

Huang

2016

WIREs Comput Mol Sci

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Water is the key to life in our planet. As one of the most abundant resources on the earth, water may play important roles in chemical reactions in addition to being a reaction medium. In this review, we highlight recent advances in experimental observations and mechanistic understanding of the promotional role of water in chemical reactions, with an emphasis on the essential effects of water in heterogeneous catalysis. As water may exist in molecular state or dissociate to hydroxyl (OH) and hydrogen (H) species on catalyst surfaces, we have outlined the roles of water from three aspects: (1) the promotional role of molecular water including the solvation-like effect and water-mediated H-transfer, (2) the promotional role of OH/OH − and H/H + species, and (3) some miscellaneous effects of water, such as water-assisted carbon removal, surface reconstruction, and active sites blocking. The results discussed here provide a fundamental understanding of the promotional role of water in heterogeneous reactions and may inspire the theoretical studies of water effects on other fields of chemistry and atmospheric science as well.

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“…Moreover, the as-prepared Co x Mn y O 4 spinel catalysts showed long-term stability in the presence of steam and maintained the activity with little fluctuation for as long as 30 h (Figure 3D). Compared with the performance of reported spinel-type catalysts, which often decayed in the first 10 h (Shen et al., 2017, Wang et al., 2014), the results demonstrated that as-prepared cobalt manganese spinel multi-shelled hollow microsphere catalysts were much more stable and very promising for practical application. The robust shield of bistratal shells can effectively retard the water poisoning, thus preserving high catalytic efficiency during CO oxidation, even under moisture-rich conditions.…”

Section: Resultsmentioning

confidence: 81%

“…Compared with literature findings, Xie and co-workers synthesized very-high-activity Co 3 O 4 nanorods with predominantly exposed {110} planes; however, the ΔT of Co 3 O 4 nanorods catalysts was as large as 277°C (Xie et al., 2009). Meanwhile, the ΔT of most reported spinel nanoparticles was also very high and in the range of 100°C–178°C (Table S2) (Song et al., 2014, Kuo et al., 2014, Shen et al., 2017, Wang et al., 2014, Yu et al., 2009, Biemelt et al., 2016). Comparatively, the ΔT values of our Co x Mn y O 4 sample can reach as low as 20°C, exhibiting the excellent water-resistent ability of Co x Mn y O 4 multi-shelled hollow microsphere catalysts.…”

Section: Resultsmentioning

confidence: 99%

Template-free Synthesis of Stable Cobalt Manganese Spinel Hollow Nanostructured Catalysts for Highly Water-Resistant CO Oxidation

Zhang

et al. 2019

iScience

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SummaryDevelopment of spinel oxides as low-cost and high-efficiency catalysts is highly desirable; however, rational synthesis of efficient and stable spinel systems with precisely controlled structure and components remains challenging. We demonstrate the design of complex nanostructured cobalt-based bimetallic spinel catalysts for low-temperature CO oxidation by a simple template-free method. The self-assembled multi-shelled mesoporous spinel nanostructures provide high surface area (203.5 m2/g) and favorable unique surface chemistry for producing abundant active sites and lead to the creation of robust microsphere configured by 16-nm spinel nanosheets, which achieve satisfactory water-resisting property and catalytic activity. Theoretical models show that O vacancies at exposed {110} facets in cubic spinel phase guarantee the strong adsorption of reactive oxygen species on the surface of catalysts and play a key role in the prevention of deactivation under moisture-rich conditions. The design concept with architecture and composition control can be extended to other mixed transition metal oxide compositions.

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A comparative study of the catalytic oxidation of HCHO and CO over Mn0.75Co2.25O4 catalyst: The effect of moisture

Cited by 90 publications

References 46 publications

Promotion effect of potassium carbonate on catalytic activity of Co₃O₄ for formaldehyde removal

Promotion effect of potassium carbonate on catalytic activity of Co₃O₄ for formaldehyde removal

The promotional role of water in heterogeneous catalysis: mechanism insights from computational modeling

Template-free Synthesis of Stable Cobalt Manganese Spinel Hollow Nanostructured Catalysts for Highly Water-Resistant CO Oxidation

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A comparative study of the catalytic oxidation of HCHO and CO over Mn0.75Co2.25O4 catalyst: The effect of moisture

Cited by 90 publications

References 46 publications

Promotion effect of potassium carbonate on catalytic activity of Co3O4 for formaldehyde removal

Promotion effect of potassium carbonate on catalytic activity of Co3O4 for formaldehyde removal

The promotional role of water in heterogeneous catalysis: mechanism insights from computational modeling

Template-free Synthesis of Stable Cobalt Manganese Spinel Hollow Nanostructured Catalysts for Highly Water-Resistant CO Oxidation

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Product

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Promotion effect of potassium carbonate on catalytic activity of Co₃O₄ for formaldehyde removal

Promotion effect of potassium carbonate on catalytic activity of Co₃O₄ for formaldehyde removal