MOLECULES
·
2024
·Vol. 29
·期 8
·1721
·
IF 4.2
Shoudong Wang,Lei Zhou,Hongyun Qin,Zixu Dong,Haoyuan Li,Bo Liu,Zhilu Wang,Lina Zhang,Qiang Fu,Xia Chen
Hydrofluorocarbons (HFCs) have important applications in different industries; however, they are environmentally unfriendly due to their high global warming potential (GWP). Hence, reclamation of used hydrofluorocarbons via energy-efficient adsorption-based separation will greatly contribute to reducing their impact on the environment. In particular, the separation of azeotropic refrigerants remains challenging, such as typical mixtures of CH2F2(HFC-23) and CHF3(HFC-32), due to a lack of adsorptive mechanisms. Metal–organic frameworks (MOFs) can provide a promising solution for the separation of CHF3–CH2F2mixtures. In this study, the adsorption mechanism of CHF3–CH2F2mixtures in TIFSIX-2-Cu-i was revealed at the microscopic level by combining static pure-component adsorption experiments, molecular simulations, and density-functional theory (DFT) calculations. The adsorption separation selectivity of CH2F2/CHF3in TIFSIX-2-Cu-i is 3.17 at 3 bar under 308 K. The existence of similar TiF62−binding sites for CH2F2or CHF3was revealed in TIFSIX-2-Cu-i. Interactions between the fluorine atom of the framework and the hydrogen atom of the guest molecule were found to be responsible for determining the high adsorption separation selectivity of CH2F2/CHF3. This exploration is important for the design of highly selective adsorbents for the separation of azeotropic refrigerants.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Molecular Catalysis
·
2023
·
IF 4.6
Shiwei Feng,Chengping Zhang,Hengdao Quan
As an environmentally friendly cleaning agent, Z -1-chloro-3,3,3-trifluoropropene (HCFO-1233zd( Z )) can realize industrial production by the isomerization of HCFO-1233zd( E ). Herein, various isomerization catalysts with different structures, compositions and acid properties were prepared through the fluorination of γ-Al 2 O 3 with CHF 3 by controlling the activation conditions. For the first time, the catalysts for HCFO-1233zd( E ) isomerization were systematically studied by XRD, N 2 physisorption, XPS, SEM, MAS NMR spectroscopy, NH 3 -TPD and py-IR. The active site of this reaction was revealed and the catalyst deactivation mechanism was proposed. It turned out that HCFO-1233zd( E ) isomerization prefers to occur at Lewis acid sites with moderate density and strength. The amorphous particles composed of γ-Al 2 O 3 , Al 2 O 3 (F) and α-AlF 3 ( R 3 ¯ c ) at 450 °C exhibit highly catalytic activity for HCFO-1233zd( E ) isomerization. After 100 h evaluation, it was found that residual γ-Al 2 O 3 can be fluorinated by HCFO-1233zd( E ) to form needle-like structures which could induce the amorphous Al 2 O 3 (F) particles to reorganize and give cubic structures, where the Lewis acid properties were enhanced, leading to catalyst deactivation.
研究领域:
催化
·
化学工程
·
材料科学
·
环境化学
✓ 已验证
产品关联
DOI
高影响因子
Catalysis Science & Technology
·
2019
·Vol. 9
·期 6
·1338-1348
·
IF 5.726
Jinchao Wang,Wenfeng Han,Shucheng Wang,Haodong Tang,Wucan Liu,Ying Li,Chunshan Lu,Jianjun Zhang,Eric M. Kennedy,Xiaonian Li
Catalytic coupling of CH4 with potent greenhouse gas CHF3 to vinylidene fluoride (VDF) was investigated over composite catalysts. Carbon-partitioned LaF3–BaF2 catalysts were prepared by PVDF (polyvinylidene fluoride)-mediated calcination. During catalyst preparation, PVDF functions as the fluorine source and carbon source. Compared with the catalysts prepared by the conventional HF co-precipitation method, the transformation of LaF3 and BaF2 to Ba1−xLaxF2+x solid solution is inhibited as Ba and La are separated by carbon layers derived from the decomposition of PVDF. The Ba1−xLaxF2+x phase is not favorable for the coupling of CH4 with CHF3 to VDF. In addition, PVDF-mediated calcination facilitates the formation of LaOF which is one of the key species for coupling of CH4 with CHF3 to VDF. O− species, which is the most active oxygen species for the activation of CH4, increases significantly following PVDF-mediated calcination due to the formation of LaOF. Consequently, the formation rate of VDF over the catalyst derived from PVDF-mediated calcination is 3.6 times higher than the HF co-precipitation catalyst at a reaction temperature of 700 °C. The formation rate of the HF co-precipitated catalyst declines to nearly half of the initial rate in a time-on-stream of 15 h. By contrast, only slight deactivation is observed over the catalyst prepared by PVDF-mediated calcination. The present work provides a promising strategy for the preparation of composite catalysts.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
INORGANIC CHEMISTRY
·
2026
·
IF 4.6
Xi-Ting Zhang,Li-Ping Zhang,Zhong-Lei Xing,Tianze Zhou,Shao-Min Wang,Qing-Yuan Yang
The coordination geometry of metal nodes is a critical yet overlooked variable in metal–organic framework (MOF) design. Here, we show that an amino substituent on the isonicotinic acid linker switches Cu(II) from five-coordinate square-pyramidal to four-coordinate square-planar, collapsing the framework from a 3D microporous network (Cu-ina, ina = isonicotinic acid) to a 2D layered structure (Cu-2ain, 2ain = 2-aminoisonicotinic acid). The amino group strengthens the Cu–N bond and eliminates one Cu–O contact, reducing the pore-limiting diameter to 3.27 Å and imposing complete size exclusion of both CHF3 (∼4.6 Å) and N2 (3.64 Å) in Cu-2ain. The 3D framework Cu-ina, free of this modification, achieves a CHF3 uptake of 50.1 cm3 g–1 at 298 K with an IAST selectivity of 46 for CHF3/N2, driven by cooperative C–H···F and C–H···O hydrogen bonding confirmed by GCMC simulations and DFT calculations. Five-cycle breakthrough experiments confirm excellent regenerability. This work demonstrates that ligand functionalization can inadvertently restructure metal coordination geometry and collapse framework dimensionality, overriding any intended surface-chemical benefit.
✓ 已验证
DOI
PubMed
高影响因子
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