The interplay between the suprafacial and intrafacial mechanisms for complete methane oxidation on substituted LaCoO3 perovskite oxides

Wang, Ting; Zhang, Chao; Wang, Jieyu; Li, Haiyan; Duan, Yan; Liu, Zheng; Lee, Jun Yan; Hu, Xiao; Xi, Shibo; Du, Yonghua; Sun, Shengnan; Liu, Xianhu; Lee, Jongmin; Wang, Chuan; Xu, Zhichuan J.

doi:10.1016/j.jcat.2020.07.007

Cited by 40 publications

(13 citation statements)

References 69 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The preedge energies of all three samples, 2Co-mSiO 2 , 5Co-mSiO 2 , and 10Co-mSiO 2 , were close to 7709 keV, which corresponds to the Co(II) oxidation state. The energy profile for all of the catalysts followed a trend very close to that for CoO, which also supports the presence of the CoO phase in the catalysts. , This analysis also supports the TPR result, which indicated a high-temperature reduction peak of >700 °C for the three samples (Figure ). Besides, the three spectra followed a similar pattern, which is an indication of the very identical structure of the catalyst irrespective of the metal loading.…”

Section: Resultssupporting

confidence: 80%

Mesoporous-Silica-Stabilized Cobalt(II) Oxide Nanoclusters for Propane Dehydrogenation

Bian

Dewangan

Wang

et al. 2021

ACS Appl. Nano Mater.

Self Cite

View full text Add to dashboard Cite

Propane dehydrogenation is a highly efficient and selective route to produce propylene. The development of transition-metal-based catalysts, especially cobalt oxide−Co(II) for propane dehydrogenation reaction has gained momentum in the past few years. However, the formation of bulk metallic cobalt is a major drawback of cobalt oxide-based catalysts, which need to be circumvented to maintain the high propylene selectivity. In this study, a facile route is proposed to prepare stable Co(II) on a mesoporous silica matrix (Co-mSiO 2 ) via a simple synthesis procedure using the neutral templating method. The cobalt content in the silica is varied to optimize the activity and stability during the reaction. The physicochemical properties of the catalyst measured using X-ray diffraction, N 2 adsorption−desorption, and transmission electron microscopy revealed the high surface area and well-dispersed cobalt oxide present in the mesoporous silica matrix. The coordination geometry found from the UV−vis and extended X-ray absorption fine structure analysis showed that Co(II) is highly dispersed with tetrahedral coordination in the mesoporous silica. The Co-mSiO 2 catalyst with the lowest cobalt content of 2 wt % tested for the propane dehydrogenation reaction at the operating temperature of 600 °C showed 36% propane conversion with 94% propylene selectivity. 2Co-mSiO 2 showed the nonredox properties of Co(II) with negligible metallic cobalt formed and a lower coke deposition rate (4 mg carbon /g cat. •h) after the reaction supported by X-ray absorption near-edge structure and thermogravimetric analysis. The source for the side reaction (coke formation) can be assigned to the strong adsorption of propylene, which was unraveled using Fourier transform infrared analysis, and a nonredox mechanism is proposed for propane dehydrogenation reaction over the 2Co-mSiO 2 catalyst.

show abstract

Section: Resultssupporting

confidence: 80%

Mesoporous-Silica-Stabilized Cobalt(II) Oxide Nanoclusters for Propane Dehydrogenation

Bian

Dewangan

Wang

et al. 2021

ACS Appl. Nano Mater.

Self Cite

View full text Add to dashboard Cite

show abstract

“…It is noticeable that pristine La 2 CuO 4 with such a deep d orbital energy can hardly transfer electrons to activate molecular oxygen. 54 This corresponded well with the O 2 -TPD result of the weakest desorption of the surface adsorbed oxygen (O α ) on the La 2 CuO 4 surface. As compared to that of La 2 CuO 4 , Mn substitution increased the d-band center value closer to the Fermi level.…”

Section: Resultssupporting

confidence: 80%

“…And both Cu + and fewer oxygen vacancies were found to maintain electrical neutrality. According to a previous report, 54 there was an equilibrium between the B-position metal valence and the oxygen vacancy content: Cu 2+ –O 2− –Mn 4+ ↔ Cu + –O vac –Mn 3+ , and the equilibrium position is determined by temperature and the intrinsic properties of catalysts. Thus, the catalytic activities were greatly related to the reaction temperature and Mn ratio.…”

Section: Resultsmentioning

confidence: 91%

See 1 more Smart Citation

Activation of molecular oxygen over Mn-doped La₂CuO₄perovskite for direct epoxidation of propylene

Zhang

Dai

Ding

et al. 2022

Catal. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…As compared to pure LaCoO 3 sample, the d states of Cu, Co, and La, along with p states of O of LaCo x Cu1 –x O 3−δ were found to deviate toward a deeper or lower energy. It is noticeable that the d orbital of metal can transfer electrons to the p orbital of oxygen along with weakening process of O–O bond . Especially in this case, the d states of Cu and Co move to deeper energy below the Fermi level after Cu doping, which is consistent with the adsorption energy and charge data.…”

Section: Resultssupporting

confidence: 84%

Insight into the Effect of Copper Substitution on the Catalytic Performance of LaCoO₃-Based Catalysts for Direct Epoxidation of Propylene with Molecular Oxygen

Lei

Dai

Tan

et al. 2021

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

Direct epoxidation of propylene to propylene oxide (PO) with molecular oxygen as the most atomically economical route remains challenging due to the low PO yield. In this study, CuO supported on perovskites (LaCoO 3 ) modified with NaCl was found to be active for direct epoxidation of propylene with oxygen. LaCo x Cu 1−x O 3− modified with alkali metal salts were further fabricated to improve catalytic performance with the assistance of citric acid. Among the investigated catalysts, LaCo 0.8 Cu 0.2 O 3−δ exhibited the best catalytic performance, with a PO formation rate of 60.4 g PO •kg cat −1•h −1 (PO selectivity of 10.2% and propylene conversion of 12.0%) at a lower temperature (250 °C). The characterization results indicate that Cu-doped LaCoO 3 catalysts with enhanced oxygen vacancies and abundant electrophilic oxygen species are crucial to selectively attack on CC bond instead of C−H bond. Besides, LaCo x Cu 1−x O 3−δ catalysts demonstrated higher propylene conversion and more stable catalytic performance. This work exemplifies the direct propylene epoxidation with molecular oxygen employing perovskite materials.

show abstract

The interplay between the suprafacial and intrafacial mechanisms for complete methane oxidation on substituted LaCoO3 perovskite oxides

Cited by 40 publications

References 69 publications

Mesoporous-Silica-Stabilized Cobalt(II) Oxide Nanoclusters for Propane Dehydrogenation

Mesoporous-Silica-Stabilized Cobalt(II) Oxide Nanoclusters for Propane Dehydrogenation

Activation of molecular oxygen over Mn-doped La₂CuO₄perovskite for direct epoxidation of propylene

Insight into the Effect of Copper Substitution on the Catalytic Performance of LaCoO₃-Based Catalysts for Direct Epoxidation of Propylene with Molecular Oxygen

Contact Info

Product

Resources

About

The interplay between the suprafacial and intrafacial mechanisms for complete methane oxidation on substituted LaCoO3 perovskite oxides

Cited by 40 publications

References 69 publications

Mesoporous-Silica-Stabilized Cobalt(II) Oxide Nanoclusters for Propane Dehydrogenation

Mesoporous-Silica-Stabilized Cobalt(II) Oxide Nanoclusters for Propane Dehydrogenation

Activation of molecular oxygen over Mn-doped La2CuO4perovskite for direct epoxidation of propylene

Insight into the Effect of Copper Substitution on the Catalytic Performance of LaCoO3-Based Catalysts for Direct Epoxidation of Propylene with Molecular Oxygen

Contact Info

Product

Resources

About

Activation of molecular oxygen over Mn-doped La₂CuO₄perovskite for direct epoxidation of propylene

Insight into the Effect of Copper Substitution on the Catalytic Performance of LaCoO₃-Based Catalysts for Direct Epoxidation of Propylene with Molecular Oxygen