Volcano correlations between formal potential and Hammett parameters of substituted cobalt phthalocyanines and their activity for hydrazine electro-oxidation

Geraldo, Daniela A.; Linares, Cristian; Chen, Yo-Ying; Ureta‐Zañartu, Soledad; Zagal, José H.

doi:10.1016/s1388-2481(01)00300-9

Cited by 68 publications

(24 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This has been observed by Scherson et al 18 for the reduction of O 2 catalyzed by Fe(II) porphyrins. Figure 2A shows the volcano correlation published previously and clearly indicates that an optimum Co(II)/(I) formal potential 4,15,16 exists for having maximum catalytic activity for the reaction. Figure 2B shows the same data of Figure 2B but plotted as (log k) E versus E, where E = E o -E N2H4/N2.…”

Section: Discussionsupporting

confidence: 61%

“…Co phthalocyanines and vitamin B 12 (as aquocobalamine), when adsorbed on graphite electrode catalyze this reaction. 4,[7][8][9][10][11][12][13][14][15][16][17] The following mechanism has been proposed, 15 …”

Section: Discussionmentioning

confidence: 99%

“…Figure 1 shows a series of cyclic voltammograms taken from previous work 15 illustrating the response of some adsorbed CoPc Increasing the electron-withdrawing power of the groups on the ligand causes a shift of the Co(II)/(I) process to more positive potentials. The foot of the wave corresponding to hydrazine oxidation is also shown.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Matching the Catalyst Co(II)/(I) Formal Potential of a Macrocyclic Complex to the Reversible Potential of Hydrazine Oxidation for the Highest Activity

Recio¹,

Geraldo²,

Cañete³

et al. 2013

ECS Electrochemistry Letters

View full text Add to dashboard Cite

In this work we have re-interpreted volcano correlations for the oxidation of hydrazine catalyzed by CoMN4 catalysts and found that the highest catalytic activity is observed when the formal potential of the catalyst matches the reversible potential of the reaction, i.e. the hydrazine/dinitrogen reversible potential, that is −0.4959 V vs. SCE at pH 13. This clearly shows that the formal potential of the catalysts needs to be "tuned" or to be very close to the reversible potential of the target molecule to undergo an ET process. This is also true for other reactions we are studying.Electrocatalysis is present in many processes of technological relevance. These electron transfer (ET) reactions involve molecules that for reacting at desired rates, apart from an overpotential, they require the interaction of reactants, intermediates or products with active sites on the electrode surface. 1-3 It is very important to understand the fundamentals of electrocatalysis in order to design better catalytic electrode materials. 1-4 In particular, MN4 macrocyclic complexes like phthalocyanines and porphyrins, when adsorbed on electrode surfaces, catalyze a myriad of electrochemical reactions and in many cases the activity plotted versus the formal potential of the catalyst give volcano correlations. 4 We have shown the importance of "tuning" the formal potential of MN4 macrocyclic complexes for optimizing the electrocatalytic activity of these species for many reactions. 3,4 However in previous work no reference to the reversible potential of the reaction under study has been made. In this work we have re-interpreted data previously published in the literature related to the electrooxidation of hydrazine catalyzed by CoN4 macrocycles adsorbed on graphite electrodes and propose a new mechanism for the reaction. Further, we have found that for Co macrocyclics, in a volcano correlation, the maximum activity is observed for the catalyst that has a formal potential very close or equal to the reversible potential of the hydrazine/dinitrogen couple. This is also true for Fe macrocyclics. 5 This finding is very important since it suggests that to design a catalyst, its formal potential need to be tuned so to approach the reversible potential of the reaction to be catalyzed under the experimental conditions. This seems to be true for other reactions, like the oxidation of L-cysteine catalyzed by CoN4 macrocyclic complexes. 6

show abstract

Section: Discussionsupporting

confidence: 61%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Matching the Catalyst Co(II)/(I) Formal Potential of a Macrocyclic Complex to the Reversible Potential of Hydrazine Oxidation for the Highest Activity

Recio¹,

Geraldo²,

Cañete³

et al. 2013

ECS Electrochemistry Letters

View full text Add to dashboard Cite

show abstract

“…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%

Oxygen Reduction Reaction at Penta-Coordinated Co Phthalocyanines

et al. 2020

View full text Add to dashboard Cite

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.

show abstract

“…The electrocatalytic activity of modified electrodes has been studied by many researchers (Kim et al 2011;Li, Xie, and Chen 2011;Ameena, Akhtarb, and Shin 2012). A wide variety of organic and inorganic substances including iron phthalocyanine (Ozoemena and Nyokong 2005), pyrocatechol violet (Golabi, Zare, and Hamzehloo 2001), cobalt phthalocyanine (Geraldo et al 2002), molybdenum oxide (Koçak, Ertaş, and Dursun 2013), platinum nanoparticles, molybdenum oxide (Cakar et al 2013), pulse deposited platinum, molybdenum oxide (Yavuz et al 2015) and pyrogallol red (Ensafi and Mirmomtaz 2005) have been used for the preparation of modified electrodes to enhance electron transfer.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Determination of Hydrazine at Gold and Platinum Nanoparticles Modified Poly(L-Serine) Glassy Carbon Electrodes

Koçak¹,

Altın²,

Koçak³

2015

Analytical Letters

View full text Add to dashboard Cite

L-serine monomer was polymerized electrochemically on a glassy carbon electrode by cyclic voltammetry. After L-serine polymerization, gold and platinum metal nanoparticles were doped by electrochemical reduction on the surface. The modified electrodes were characterized by Downloaded by [UQ Library] at 23:20 13 June 2015 2 using scanning electron microscopy and electrochemical impedance spectroscopy. The electrochemical behavior of hydrazine oxidation at the electrodes was investigated in 0.1 M pH 7.0 phosphate buffer. Hydrazine oxidation peaks were observed at 650, 399, 280, and 395 mV at the bare glassy carbon , poly(L-serine) modified glassy carbon, gold nanoparticle modified poly(L-serine) film glassy carbon electrode, and platinum nanoparticles modified poly(L-serine) film glassy carbon electrode, respectively. The most active surface towards hydrazine oxidation was the platinum nanoparticle modified poly(L-serine) film glassy carbon electrode with a 1045 mV negative potential shift and approximately three-fold higher peak current. The hydrazine oxidation peak was shifted to a 370 mV negative potential with a 2.5 times higher current at the gold nanoparticle modified poly(L-serine) film glassy carbon electrode compared to the bare electrode. The linear concentration ranges were from 1.0 to 1000 µM and 0.5 to 1000 µM for the gold nanoparticle modified poly(L-serine) film glassy carbon and the platinum nanoparticles modified poly(L-serine) film glassy carbon electrodes with limits of detections of 0.5 and 0.2 µM, respectively.

show abstract

Volcano correlations between formal potential and Hammett parameters of substituted cobalt phthalocyanines and their activity for hydrazine electro-oxidation

Cited by 68 publications

References 21 publications

Matching the Catalyst Co(II)/(I) Formal Potential of a Macrocyclic Complex to the Reversible Potential of Hydrazine Oxidation for the Highest Activity

Matching the Catalyst Co(II)/(I) Formal Potential of a Macrocyclic Complex to the Reversible Potential of Hydrazine Oxidation for the Highest Activity

Oxygen Reduction Reaction at Penta-Coordinated Co Phthalocyanines

Electrochemical Determination of Hydrazine at Gold and Platinum Nanoparticles Modified Poly(L-Serine) Glassy Carbon Electrodes

Contact Info

Product

Resources

About