Biomimicking vitamin B12. A Co phthalocyanine pyridine axial ligand coordinated catalyst for the oxygen reduction reaction

Riquelme, Jorge; Neira, Karinna; Marco, José F.; Hermosilla-Ibáñez, Patricio; Orellana, Walter; Zagal, José H.; Tasca, Federico

doi:10.1016/j.electacta.2018.01.177

Cited by 61 publications

(54 citation statements)

References 64 publications

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“…In Figure 1 we report a schematic representation of CoPc, 16(F)CoPc and 8(2-Et-C 6 H 11 O)CoPc molecules ( Figure 1A) and the corresponding molecule coordinated to the pyridine modified CNT (i.e., CoN4-Py-CNT) ( Figure 1B). The modification of CNTs with pyridine moieties to form Py-CNT has been reported previously (Bahr and Tour, 2001;Tasca et al, 2011;Tuci et al, 2014;Venegas et al, 2017;Riquelme et al, 2018a). Also, the modification of CoN4 with pyridine or similar strongly…”

Section: Resultsmentioning

confidence: 71%

“…coordinating solvents has been shown before (Cariati et al, 1975;Liao and Scheiner, 2001;Riquelme et al, 2018a). Nevertheless, the synthesis and the studies of the ORR at substituted pentacoordinated CoPc have not been reported before.…”

Section: Resultsmentioning

confidence: 99%

“…The EPR spectrum of the complexes in the presence of CNT, are shown in Figure 2B. CNT powder has a strong signal due to defects in the graphene structure (Corzilius et al, 2007;Riquelme et al, 2018a) with a g factor value of 2.055 (Riquelme et al, 2018a). The signal of CNT modified with the various Co phthalocyanines, varies in each sample ( Figure 2B), indicating the electronic interaction between the CNT and the adsorbed moieties.…”

Section: Epr and Xps Characterizationmentioning

confidence: 99%

“…In particular, Co phthalocyanine (CoPc) was reported to be an electrocatalysts for the oxygen reduction reaction (ORR) by Jasinski (1964). Later the activity of those complexes was studied for other important reaction like the CO 2 reduction (Morlanes et al, 2016;Zhang et al, 2017), and the oxidation of L-cysteine (Gulppi et al, 2014), hydrazine (Geraldo et al, 2002(Geraldo et al, , 2008Venegasa et al, 2017), thiocyanate (Linares-Flores et al, 2012) and thiols (Bedioui et al, 2007) and also for their bio-mimicking activity (Zagal et al, 2010;Venegas et al, 2017;Herrera et al, 2018;Riquelme et al, 2018a). The search for electrocatalysts for the ORR as active and durable as the rare and costly Pt (which is the industrial standard for this reaction) is still pushing the search for a non-precious metal catalyst.…”

Section: Introductionmentioning

confidence: 99%

“…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%

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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: Resultsmentioning

confidence: 71%

Section: Resultsmentioning

confidence: 99%

Section: Epr and Xps Characterizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Oxygen Reduction Reaction at Penta-Coordinated Co Phthalocyanines

et al. 2020

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Recent Advances in Non‐Precious Metal Single‐Atom Electrocatalysts for Oxygen Reduction Reaction in Low‐Temperature Polymer‐Electrolyte Fuel Cells

Sarapuu,

Lilloja,

Akula

et al. 2023

ChemCatChem

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Fuel cells have emerged as a promising clean energy technology with a great potential in various sectors, including transportation and power generation. However, the high cost and scarcity of the noble metals currently used to synthesise electrocatalysts for low‐temperature fuel cells has hindered their widespread commercialisation. In recent decades, the development of non‐precious metal electrocatalysts for the cathodic oxygen reduction reaction (ORR) have gained significant attention. Among those, electrocatalysts with atomically dispersed active sites, referred to as single‐atom catalysts (SACs), are gaining more interest. Nanocarbon materials containing single transition metal atoms coordinated to nitrogen atoms are active electrocatalysts for the ORR in both acidic and alkaline conditions and thus have a great promise to be utilised as non‐precious metal cathode electrocatalysts in low‐temperature fuel cells. This review article provides an overview of the recent advancements in the utilisation of transition metal‐based SACs in proton exchange membrane fuel cells (PEMFCs) and anion exchange membrane fuel cells (AEMFCs). We highlight the main strategies and synthetic approaches for tailoring the properties of SACs to enhance their ORR activity and durability. Based on the already achieved results, it is evident that SACs indeed could be suitable for the cathode of the low‐temperature fuel cells.

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Immobilisation of Iron Porphyrin from an Equilibrium Solution with Diazonium‐Functionalised Axial Ligand: Dependence of Film Composition on Grafting Potential

Brooksby

Fitchett

et al. 2021

ChemElectroChem

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In dichloromethane solution, tetraphenylporphyrin iron (III) chloride (FeTPPCl) and 4‐(1H‐Imidazol‐1‐yl)aniline (Im‐Ph‐NH2) exist in equilibrium with axially‐coordinated [FeTPP(Im‐Ph‐NH2)n]+ (n=1 and 2). After in situ diazotisation of Im‐Ph‐NH2, electroreduction of the diazonium ion leads to deposition of a film incorporating [FeTPP(Im‐Ph)2]+ and uncoordinated Im‐Ph. In the 1 : 1 FeTPPCl:Im‐Ph‐NH2 grafting solution used in this work, Im‐Ph‐NH2 is mostly uncoordinated. However, the formation constant for axially coordinated Fe(II)TPP is significantly greater than for Fe(III)TPP+. Consequently, the relative amounts of coordinated and uncoordinated Im‐Ph in the films depends on whether the grafting scans traverse the potential for reduction of FeTPPCl. In addition, redox grafting can occur based on the Fe(III)/(II) couple of solution‐ and film‐based porphyrin. Electrochemistry, atomic force microscopy and X‐ray photoelectron spectroscopy reveal that the relative amount of free and coordinated Im‐Ph, and concentration of [FeTPP(Im‐Ph)2]+ in the films depend on the negative potential limit during grafting.

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Biomimicking vitamin B12. A Co phthalocyanine pyridine axial ligand coordinated catalyst for the oxygen reduction reaction

Cited by 61 publications

References 64 publications

Oxygen Reduction Reaction at Penta-Coordinated Co Phthalocyanines

Oxygen Reduction Reaction at Penta-Coordinated Co Phthalocyanines

Recent Advances in Non‐Precious Metal Single‐Atom Electrocatalysts for Oxygen Reduction Reaction in Low‐Temperature Polymer‐Electrolyte Fuel Cells

Immobilisation of Iron Porphyrin from an Equilibrium Solution with Diazonium‐Functionalised Axial Ligand: Dependence of Film Composition on Grafting Potential

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