Axial ligand effect on the catalytic activity of biomimetic Fe-porphyrin catalyst: An experimental and DFT study

Christoforidis, Konstantinos C.; Pantazis, Dimitrios A.; Bonilla, L. L.; Bletsa, Eleni; Louloudi, Maria; Deligiannakis, Yiannis

doi:10.1016/j.jcat.2016.08.013

Cited by 23 publications

(17 citation statements)

References 86 publications

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“…Indeed, this was a synergism of the two factors, especially the coordination, elevated the catalytic activity of Co TPFPP/np‐CTS and resulted in always increasing of TOF until 3.5 h. After 3.5‐h reaction time, the TOFs (or TON)obtained from the cyclohexane oxidation over Co TPFPP/np‐CTS showed dropping down, due mainly to the more and more effect of the produced more hexane diacid on the catalytic activity of the catalyst. The nitrogen atom of the axial ligand (−NH 2 ) in Co TPFPP/np‐CTS was protonated, this action was similar to the nitrogen atom situation of the axial imidazole as‐reported , (a) versus (c)) was not changed obviously by ICP‐OES analyses.…”

Section: Resultssupporting

confidence: 75%

“…This is becausethat, (1) the electron cloud density of the bound nitrogen atom of the axial ligand (−NH 2 ) in Co TPFPP/np‐CTS decreased. It indicated the strong coordination of amino to cobalt porphyrin, and resulted in more effect to activate O 2 ,, just as the XPS‐analyzed result above. (2) the nano‐cavity of CTS benefited to cyclohexane and O 2 accessing the active sites.…”

Section: Resultsmentioning

confidence: 57%

“…This natural structure makes the enzyme, its related artificial enzyme and biomimetic catalyst having excellent functionality and becoming an important catalyst used for substrate oxidation . Duplication of the core structure and part functions of the enzyme using immobilized metalloporphyrin systems is of tremendous interest in order to improve the performance (activity and reusability) of metalloporphyrins . The effect of N‐bases axial coordination on the catalytic activity of metalloporphyrin has been studied about 20–30 years ago, and some achievements were obtained ,.…”

Section: Introductionmentioning

confidence: 99%

“…The effect of N‐bases axial coordination on the catalytic activity of metalloporphyrin has been studied about 20–30 years ago, and some achievements were obtained ,. At present, some new studies on the effect of the axial ligand on catalytic activity of metalloporphyrins,, suggested that, the enhanced catalytic activity was attributed to the increased electron donation ability and favoring the formation of the ferryl‐oxo species, and that the “push” effect prevails over the “pull” effect . The studies suggested that, the coordination of the axial ligand made O 2 more activated than the free O 2, and triggered the catalytic oxidation processes.…”

Section: Introductionmentioning

confidence: 99%

“…We have not only found that, a sulfur‐ or nitrogen‐containing ligand in the corresponding support could affect the binding energy of the metal center in metalloporphyrins and then promote the catalytic activity of the immobilized metalloporphyrin, but also found that, each of the catalysts (Co TCPP/ZnS, or Fe TPPS/pd‐CTS) could be only reused 2 times respectively for the oxidation of cyclohexane ,. The experiences above,,,encouraged us to consider the stability issue of immobilized metalloporphyrin catalyst: the hexane diacid produced in the cyclohexane oxidation system, will affect the activity and reusability of the immobilized metalloporphyrin catalysts. This is a newly‐discovered issue for preparing an immobilized metalloporphyrin catalyst with high catalytic activity and multiple reusability.…”

Section: Introductionmentioning

confidence: 99%

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Highly Active Catalysis of Cobalt Tetrakis(pentafluorophenyl)porphyrin Promoted by Chitosan for Cyclohexane Oxidation in Response‐Surface‐Methodology‐Optimized Reaction Conditions

Huang

Yuan

et al. 2019

ChemistryOpen

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We aimed at elevating catalytic performances of cobalt tetrakis(pentafluorophenyl)porphyrin (Co TPFPP) through axial coordination, nanocavities, and covalently grafting action. The Co TPFPP was immobilized onto nanoporous and nonporous chitosan, forming Co TPFPP/np‐ and nonp‐CTS catalysts, respectively. The catalysts were characterized by various spectroscopic techniques. The catalytic performances of these catalysts for cyclohexane oxidation under response‐surface‐methodology‐optimized oxidation reaction conditions were estimated and compared. Co TPFPP/np‐CTS was an excellent catalyst at aspect of catalytic activity, exhibiting the considerable potential reusability, 24.2 mol % yields (KA oil : cyclohexanone and cyclohexanol) in average, and total turnover frequencies (TOFs) of 3.25×106 h−1. This is attributed to the structural characteristics of the Co TPFPP/np‐CTS catalyst: the cobalt porphyrin molecules could be highly scattered on CTS, forming the independent active sites, and were not leached. The axial coordination exerted the most important effect on the catalytic activity, and the covalent grafting action had a decisive effect on the increase of the total TOFs and on the reusability of the catalyst.

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Section: Resultssupporting

confidence: 75%

Section: Resultsmentioning

confidence: 57%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Highly Active Catalysis of Cobalt Tetrakis(pentafluorophenyl)porphyrin Promoted by Chitosan for Cyclohexane Oxidation in Response‐Surface‐Methodology‐Optimized Reaction Conditions

Huang

Yuan

et al. 2019

ChemistryOpen

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Simultaneously Realizing Rapid Electron Transfer and Mass Transport in Jellyfish‐Like Mott–Schottky Nanoreactors for Oxygen Reduction Reaction

Sun

Wang

Zhang

et al. 2020

Adv Funct Materials

220

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Fundamental understanding of constructing elevated catalysts to realize fast electron transfer and rapid mass transport in oxygen reduction reaction (ORR) chemistry by interface regulation and structure design is important but still ambiguous. Herein, a novel jellyfish-like Mott-Schottkytype electrocatalyst is developed to realize fast electron transfer and decipher the structure-mass transport connection during ORR process. Both spectroscopy techniques and density functional theory calculation demonstrate electrons spontaneously transfer from Fe to N-doped graphited carbon at the heterojunction interface, thus accelerating electron transfer from electrode to reactant. Dynamic analysis indicates unique structure can significantly improve mass transport of oxygen-species due to two factors: one is electrolyte streaming effect caused by tentacle-like carbon nanotubes; the other is effective collision probability in the semiclosed cavity. Therefore, this Mott-Schottky-type catalyst delievers superior ORR performance with high onset potential, positive half wave potential, and large current density. It also exhibits low overpotential when serving as an air cathode in Zn-air batteries. This work deepens understanding of the two key factors-electron transfer and mass transport-on determining the kinetic reaction of ORR process and offers a new avenue in constructing efficient Mott-Schottky electrocatalysts.

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Unraveling the Origin of Sulfur‐Doped Fe‐N‐C Single‐Atom Catalyst for Enhanced Oxygen Reduction Activity: Effect of Iron Spin‐State Tuning

et al. 2021

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Heteroatom doped atomically dispersed Fe 1 -NC catalysts have been found to show excellent activity toward oxygen reduction reaction (ORR). However,t he origin of the enhanced activity is still controversial because the structurefunction relationship governing the enhancement remains elusive.Herein, sulfur(S)-doped Fe 1 -NC catalyst was obtained as amodel, which displays asuperior activity for ORR towards the traditional Fe-NC materials. 57 Fe Mçssbauer spectroscopy and electron paramagnetic resonance spectroscopyr evealed that incorporation of Si nt he second coordination sphere of Fe 1 -NC can induce the transition of spin polarization configuration. Operando 57 Fe Mçssbauer spectra definitively identified the low spin single-Fe 3+ -atom of C-FeN 4 -S moiety as the active site for ORR. Moreover,DFT calculations unveiled that lower spin state of the Fe center after the Sd oping promotes OH* desorption process.T his work elucidates the underlying mechanisms towards Sd oping for enhancing ORR activity, and paves aw ay to investigate the function of broader heteroatom doped Fe 1 -NC catalysts to offer ageneral guideline for spin-state-determined ORR.

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Axial ligand effect on the catalytic activity of biomimetic Fe-porphyrin catalyst: An experimental and DFT study

Cited by 23 publications

References 86 publications

Highly Active Catalysis of Cobalt Tetrakis(pentafluorophenyl)porphyrin Promoted by Chitosan for Cyclohexane Oxidation in Response‐Surface‐Methodology‐Optimized Reaction Conditions

Highly Active Catalysis of Cobalt Tetrakis(pentafluorophenyl)porphyrin Promoted by Chitosan for Cyclohexane Oxidation in Response‐Surface‐Methodology‐Optimized Reaction Conditions

Simultaneously Realizing Rapid Electron Transfer and Mass Transport in Jellyfish‐Like Mott–Schottky Nanoreactors for Oxygen Reduction Reaction

Unraveling the Origin of Sulfur‐Doped Fe‐N‐C Single‐Atom Catalyst for Enhanced Oxygen Reduction Activity: Effect of Iron Spin‐State Tuning

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