Axial ligands tailoring the ORR activity of cobalt porphyrin

Zhou, Yue; Xing, Yong-Fang; Wen, Jing; Ma, Haibo; Wang, Feng‐Bin; Xia, Xing‐Hua

doi:10.1016/j.scib.2019.07.003

Cited by 70 publications

(36 citation statements)

References 49 publications

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“…If we consider the activities for CoN4 published in Zagal and Koper (2016), Venegasa et al (2017) and we correlate them with the calculated O 2 binding energy we can derive a linear correlation belonging to one side of a volcano correlation (Zagal and Koper, 2016). Also Zhou and collaborators showed an incremented activity toward the ORR increasing the electro-withdrawing force of the axial ligand coordinated to Co porphyrins (Zhou et al, 2019). This correlation would also be linear (i.e., only in one side the volcano).…”

Section: Electrochemical Characterizationmentioning

confidence: 95%

“…Penta-coordinated complexes involve a Co center coordinated to 4 planar N atoms and an axial N belonging to a pyridine molecule as for example in VB12 seem to promote a 4-e process. CoPc-Py-CNT complex also promotes the reduction of dioxygen following a mixed 2 and 4-electrons process (Zagal et al, 2010;Fukuzumi et al, 2018;Riquelme et al, 2018a;Zhou et al, 2019). Recently, Zhou and collaborators studied the effect of various axial ligands on the activity of Co porphyrin toward the ORR (Zhou et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

“…CoPc-Py-CNT complex also promotes the reduction of dioxygen following a mixed 2 and 4-electrons process (Zagal et al, 2010;Fukuzumi et al, 2018;Riquelme et al, 2018a;Zhou et al, 2019). Recently, Zhou and collaborators studied the effect of various axial ligands on the activity of Co porphyrin toward the ORR (Zhou et al, 2019). They found that an increased coordination strength of the axial ligand leads to higher activity of the catalyst (Zhou et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

“…Recently, Zhou and collaborators studied the effect of various axial ligands on the activity of Co porphyrin toward the ORR (Zhou et al, 2019). They found that an increased coordination strength of the axial ligand leads to higher activity of the catalyst (Zhou et al, 2019). Because of the presence of the fifth coordination the d orbitals of the Co redox center would become more similar to the orbitals of O 2 and therefore Co would form a stronger bond with O 2 .…”

Section: Introductionmentioning

confidence: 99%

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Oxygen Reduction Reaction at Penta-Coordinated Co Phthalocyanines

et al. 2020

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From the early 60s, Co complexes, especially Co phthalocyanines (CoPc) have been extensively studied as electrocatalysts for the oxygen reduction reaction (ORR). Generally, they promote the 2-electron reduction of O 2 to give peroxide whereas the 4-electron reduction is preferred for fuel cell applications. Still, Co complexes are of interest because depending on the chemical environment of the Co metal centers either promote the 2-electron transfer process or the 4-electron transfer. In this study, we synthetized 3 different Co catalysts where Co is coordinated to 5 N atoms using CoN4 phthalocyanines with a pyridine axial linker anchored to carbon nanotubes. We tested complexes with electro-withdrawing or electro-donating residues on the N4 phthalocyanine ligand. The catalysts were characterized by EPR and XPS spectroscopy. Ab initio calculations, Koutecky-Levich extrapolation and Tafel plots confirm that the pyridine back ligand increases the CoO 2 binding energy, and therefore promotes the 4-electron reduction of O 2. But the presence of electron withdrawing residues, in the plane of the tetra N atoms coordinating the Co, does not further increase the activity of the compounds because of pull-push electronic effects.

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Section: Electrochemical Characterizationmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Oxygen Reduction Reaction at Penta-Coordinated Co Phthalocyanines

et al. 2020

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“…In contrast to homogeneous catalysis in organic media, 30 produces only H 2 O 2 when immobilized on gold self-assembled monolayers. [48] Immobilization is achieved via ligation of Co in an axial position. Consequently, these catalysts do see kinetic improvements from the "push effect" of an axial ligand, as noted above for Fe-porphyrins.…”

Section: Cobalt Porphyrinsmentioning

confidence: 99%

Recent Developments in Metalloporphyrin Electrocatalysts for Reduction of Small Molecules: Strategies for Managing Electron and Proton Transfer Reactions

Zhang

Warren

2020

ChemSusChem

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Porphyrins are archetypal ligands in inorganic chemistry. The last 10 years have seen important new advances in the use of metalloporphyrins as catalysts in the activation and reduction of small molecules, in particular O 2 and CO 2. Recent developments of new molecular designs, scaling relationships, and theoretical modeling of mechanisms have rapidly advanced the utility of porphyrins as electrocatalysts. This Minireview focuses on the summary and evaluation of recent developments of metalloporphyrin O 2 and CO 2 reduction electrocatalysts, with an emphasis on contrasting homogeneous and heterogeneous electrocatalysis. Comparisons for proposed reaction mechanisms are provided for both CO 2 and O 2 reduction, and ideas are proposed about how lessons from the last decade of research can lead to the development of practical, applied porphyrin-derived catalysts.

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Metal Centers Drive Selectivity of Electrocatalytic Oxygen Reduction Reaction Promoted by Tetrapyrazinoporphyrazine Complexes

Sordello,

Azzi,

Pellegrino

et al. 2024

Advanced Sustainable Systems

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Fuel cells represent a promising technology for the future decarbonization of the mobility sector. However, the efficient use of H2 and O2 to produce electricity still requires noble metal catalysts such as platinum and ruthenium. In particular, the Oxygen Reduction Reaction (ORR) is complex and limiting due to its mechanism, which involves the transfer of four electrons and four protons to produce water. The search for alternative catalysts exhibiting high selectivity is progressing at a rapid pace. In this context, this group previously unveiled a homogeneous catalyst based on titanium‐centered tetrapyrazinoporphyrazines (TPyzPz) for the ORR, noting a certain modularity in the selectivity toward either a two‐ or four‐electron reduction reaction. In this study, the influence of different metal centers (magnesium (Mg), cobalt (Co), copper (Cu), and zinc (Zn)) and various substituents is investigated on the tetrapyrazinoporphyrazine ring. The findings indicate a strong dependence of activity and selectivity on these modifications. Notably, cobalt and copper catalysts exhibit a selectivity greater than 90% toward H2O production in the ORR. However, alterations to the macrocycle structure significantly affected the reactivity of these catalysts. These new insights highlighted the importance of careful structural design in the development of the next generation of ORR catalysts.

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Axial ligands tailoring the ORR activity of cobalt porphyrin

Cited by 70 publications

References 49 publications

Oxygen Reduction Reaction at Penta-Coordinated Co Phthalocyanines

Oxygen Reduction Reaction at Penta-Coordinated Co Phthalocyanines

Recent Developments in Metalloporphyrin Electrocatalysts for Reduction of Small Molecules: Strategies for Managing Electron and Proton Transfer Reactions

Metal Centers Drive Selectivity of Electrocatalytic Oxygen Reduction Reaction Promoted by Tetrapyrazinoporphyrazine Complexes

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