Unravelling faradaic electrochemical efficiencies over Fe/Co spinel metal oxides using surface spectroscopy and microscopy techniques

Kashyap, Varchaswal; Pandikassala, Ajmal; Singla, Gourav; Khan, Tuhin Suvra; Haider, M. Ali; Vinod, C. P.; Kurungot, Sreekumar

doi:10.1039/d2nr04170g

Cited by 7 publications

(5 citation statements)

References 108 publications

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“…As shown from DFT calculations, this effectively balances the binding strength of the oxygen intermediates involved in the rate-determining steps of ORR and OER. The key findings of the work clearly demonstrate the versatility of simple materials engineering strategies like doping, which deeply influence the intrinsic properties of the materials, leading to beneficial impacts in the domain of energy processes and devices. − ,,− , …”

Section: Discussionmentioning

confidence: 85%

Exploring Cu-Doped Co₃O₄ Bifunctional Oxygen Electrocatalysts for Aqueous Zn–Air Batteries

Behera,

Seth,

Agarwal

et al. 2024

ACS Appl. Mater. Interfaces

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The efficiency of oxygen electrocatalysis is a key factor in diverse energy domain applications, including the performance of metal−air batteries, such as aqueous Zinc (Zn)−air batteries. We demonstrate here that the doping of cobalt oxide with optimal amounts of copper (abbreviated as Cu-doped Co 3 O 4 ) results in a stable and efficient bifunctional electrocatalyst for oxygen reduction (ORR) and evolution (OER) reactions in aqueous Zn−air batteries. At high Cudoping concentrations (≥5%), phase segregation occurs with the simultaneous presence of Co 3 O 4 and copper oxide (CuO). At Cudoping concentrations ≤5%, the Cu ion resides in the octahedral (O h ) site of Co 3 O 4 , as revealed by X-ray diffraction (XRD)/Raman spectroscopy investigations and molecular dynamics (MD) calculations. The residence of Cu@O h sites leads to an increased concentration of surface Co 3+ -ions (at catalytically active planes) and oxygen vacancies, which is beneficial for the OER. Temperature-dependent magnetization measurements reveal favorable d-orbital configuration (high e g occupancy ≈ 1) and a low → high spin-state transition of the Co 3+ -ions, which are beneficial for the ORR in the alkaline medium. The influence of Cu-doping on the ORR activity of Co 3 O 4 is additionally accounted in DFT calculations via interactions between solvent water molecules and oxygen vacancies. The application of the bifunctional Cu-doped (≤5%) Co 3 O 4 electrocatalyst resulted in an aqueous Zn−air battery with promising power density (=84 mW/cm 2 ), stable cyclability (over 210 cycles), and low charge/discharge overpotential (=0.92 V).

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Section: Discussionmentioning

confidence: 85%

Exploring Cu-Doped Co₃O₄ Bifunctional Oxygen Electrocatalysts for Aqueous Zn–Air Batteries

Behera,

Seth,

Agarwal

et al. 2024

ACS Appl. Mater. Interfaces

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“…Further, calculations were also performed to calculate the energy needed for the activation of methanol over the Ni(OH) 2 (001), NiOOH(001), and CoNiOOH(001) surfaces, as shown in Figure 5 (right panel) and Figure S15. Oxygen vacancies have been shown to be important in our previous studies on the oxidation of cyclohexane to adipic acid and KA-oil over WFeCoO(OH) 47 and CoWO 4 @W 18 O 49 catalysts, 48 the OER and the oxygen reduction reaction over the CoFe 2 O 4 catalyst, 49 and oxidative methane coupling over alkali metal-doped LaCeO catalysts. 50 The DFT-optimized geometry of the methanol-adsorbed Ni(OH) 2 (001) surface is shown in Figure 5E.…”

Section: Resultsmentioning

confidence: 92%

Ternary Ni–Co–Se Nanostructure for Electrocatalytic Oxidative Value Addition of Biomass Platform Chemicals

Ganguly

Paul

Khurana

et al. 2023

ACS Appl. Energy Mater.

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Electrocatalytic hydrogen (H2) generation became a prime research topic in the last decade since H2 is a clean source of energy and combustion as it does not produce CO2. Conventional electrolysis is associated with the formation of oxygen via the oxygen evolution reaction (OER) at the anode. This kinetically sluggish multistep four-electron transfer OER process needs additional energy to split water. Substitution of the OER process by the easily oxidizable substrate oxidation reaction could be a lucrative way to get H2 at a much lower potential budget than the conventional one. Biomass-derived chemicals like bioalcohols (methanol, ethanol, glycerol (GlyOH), butanol, 5-hydroxymethylfurfural (HMF) obtained from hydrolysis or fermentation of biomass) could be easily oxidized to value-added commodity chemicals like formic acid, acetic acid, propionic acid, acetone, and 2,5-furandicarboxylic acid (FDCA) at the anode part of the electrolyzer. Thermodynamically, the bond dissociation energy of “C–H” and “O–H” bonds of these organic substrates is much lower than the “O–H” bond dissociation energy of water. So, to make the overall substrate oxidation reaction kinetically more feasible, an efficient electrocatalyst needs to be developed. Herein, we present a noble metal-free Ni1–x Co x Se electrocatalyst for efficient and selective conversion of alcohol molecules to value-added commodity chemicals. Particularly, Ni0.9Co0.1Se composition showed the best substrate oxidation activity compared to pristine NiSe, CoSe, and other state-of-the-art catalysts. The substrate scope is verified with methanol, ethanol, isopropanol, ethylene glycol (EGOH), GlyOH, and malic acid. Both experimental and theoretical understanding (DFT) established the fact that Co doping manipulates the NiII → NiIII OOH redox chemistry and accelerates the formation of active hypervalent Ni(Co)OOH species at a lower potential budget than NiOOH. For all catalyses, Ni0.9Co0.1Se shows superior activity with 80–100% product conversion along with a Faradaic yield of 80–95%.

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“…Corresponding atomic ratios of these elements are displayed in Tables S1–S5. Deconvolution of the high-resolution O 1s spectra of these catalysts reveals three peaks, which respectively correspond to the oxygen atoms in the physisorbed/chemisorbed water (O W , 529.8 eV), oxygen vacancies (O V , 531.5 eV), and lattice oxygen atoms (O L , 532.8 eV) (Figure b). , It can be noticed in Table S2 that the CoO x @NC-800 shows the highest O V contents of 69.22%, higher than that of CoO x @NC-700 (60.58%) and CoO x @NC-900 (52.47%). The presence of O V produces defect states in the band gap energy that generate free electrons on these states.…”

Section: Resultsmentioning

confidence: 99%

An Ultrastable Bifunctional Electrocatalyst Derived from a Co²⁺-Anchored Covalent–Organic Framework for High-Efficiency ORR/OER and Rechargeable Zinc–Air Battery

Yang

Fan

et al. 2023

ACS Appl. Mater. Interfaces

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It remains a great challenge to develop alternative electrocatalysts with high stability for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Herein, a bifunctional electrocatalyst composed of hollow CoO x (Co 3 O 4 /CoO) nanoparticles embedded in lamellar carbon nanofibers is derived from a Co 2+ -anchored covalent−organic framework. The asfabricated electrocatalyst (CoO x @NC-800) exhibits a half-wave potential (E 1/2 ) of 0.89 V with ultrahigh long-term stability (100% current retention after 3000 CV cycles). Together with promising OER performance, the CoO x @NC-800 based reversible Zn−air battery displays a small potential gap (0.70 V), superior to that of the commercial 20% Pt/C + RuO 2 . The density functional theory (DFT) calculations reveal that the remarkable electrocatalytic performance and stability of CoO x @NC-800 are attributed to the optimized adsorption of the *OOH intermediate and reduced free energy of the potential-limiting step. This study establishes the functionalization of COF structure for fabrication of high-performance carbon-based electrocatalysts.

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Unravelling faradaic electrochemical efficiencies over Fe/Co spinel metal oxides using surface spectroscopy and microscopy techniques

Abstract: Cobalt and iron metal-based oxide catalysts have a significant role in energy devices. To unravel some interesting param-eters, we have synthesized metal oxides of cobalt and iron (i.e. Fe2O3, Co3O4,...

Cited by 7 publications

References 108 publications

Exploring Cu-Doped Co₃O₄ Bifunctional Oxygen Electrocatalysts for Aqueous Zn–Air Batteries

Exploring Cu-Doped Co₃O₄ Bifunctional Oxygen Electrocatalysts for Aqueous Zn–Air Batteries

Ternary Ni–Co–Se Nanostructure for Electrocatalytic Oxidative Value Addition of Biomass Platform Chemicals

An Ultrastable Bifunctional Electrocatalyst Derived from a Co²⁺-Anchored Covalent–Organic Framework for High-Efficiency ORR/OER and Rechargeable Zinc–Air Battery

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Unravelling faradaic electrochemical efficiencies over Fe/Co spinel metal oxides using surface spectroscopy and microscopy techniques

Abstract: Cobalt and iron metal-based oxide catalysts have a significant role in energy devices. To unravel some interesting param-eters, we have synthesized metal oxides of cobalt and iron (i.e. Fe2O3, Co3O4,...

Cited by 7 publications

References 108 publications

Exploring Cu-Doped Co3O4 Bifunctional Oxygen Electrocatalysts for Aqueous Zn–Air Batteries

Exploring Cu-Doped Co3O4 Bifunctional Oxygen Electrocatalysts for Aqueous Zn–Air Batteries

Ternary Ni–Co–Se Nanostructure for Electrocatalytic Oxidative Value Addition of Biomass Platform Chemicals

An Ultrastable Bifunctional Electrocatalyst Derived from a Co2+-Anchored Covalent–Organic Framework for High-Efficiency ORR/OER and Rechargeable Zinc–Air Battery

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Exploring Cu-Doped Co₃O₄ Bifunctional Oxygen Electrocatalysts for Aqueous Zn–Air Batteries

Exploring Cu-Doped Co₃O₄ Bifunctional Oxygen Electrocatalysts for Aqueous Zn–Air Batteries

An Ultrastable Bifunctional Electrocatalyst Derived from a Co²⁺-Anchored Covalent–Organic Framework for High-Efficiency ORR/OER and Rechargeable Zinc–Air Battery