Enhancing oxygen and hydrogen evolution activities of perovskite oxide LaCoO<sub>3</sub><i>via</i> effective doping of platinum

Wang, Caiyun; Zeng, Lanting; Guo, Wenfeng; Gong, Cairong; Yang, Jing

doi:10.1039/c9ra05491j

Cited by 41 publications

(22 citation statements)

References 44 publications

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“…This performance was compared with those of recently reported oxide-based EWS systems (Figure 7d). [78,85,87,91,92,94,96,[102][103][104][105] The obtained results confirmed that CMO-U@CC exhibited improved electrocatalytic activity with faster kinetics and good stability.…”

Section: Aqueous Rechargeable Zinc-air Battery-driven Electrochemical Water Splittingsupporting

confidence: 64%

In Situ Grown CoMn₂O₄ 3D‐Tetragons on Carbon Cloth: Flexible Electrodes for Efficient Rechargeable Zinc–Air Battery Powered Water Splitting Systems

Janani

Surendran

Choi

et al. 2021

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oxygen evolution reaction and oxygen reduction reaction (OER and ORR) play important roles in rechargeable zinc-air battery (ZAB), whereas OER and hydrogen evolution reaction (HER) are the core reactions in EWS. [4,5] These electrochemical reactions exhibit sluggish kinetics because they require multistep protoncoupled electron transfers, which increase the overpotentials of the systems, thus causing the losses of considerable energy and long-term electrocatalytic activity. [6][7][8][9] Multifunctional electrocatalysts that efficiently catalyzes diverse electrochemical reactions (OER, HER, and ORR) have recently attracted considerable attention. Multifunctional electrocatalysts can reduce the manufacturing cost of the specific electrocatalysts for various electrochemical systems. The state-of-the-art catalysts such as Pt-based electrocatalysts (ORR and HER), IrO 2 and RuO 2 (OER) could not meet the characteristics of ideal multifunctional electrocatalysts because of high cost, non-abundancy, and non-multifunctional electrocatalytic activity. [10] Moreover, there are limited reports on the strategies for synthesizing multi functional electrocatalysts with intense activity, stability, and selectivity; [11][12][13] and this has necessitated the development of inexpensive, abundant, efficient, and stable multifunctional electrocatalysts to substitute the noble metal-based electrocatalysts.Transition metal oxides (TMOs) have been recently identified as the most promising alternatives to noble metal-based electrocatalysts because of their natural abundance, environmental sustainability, and superior thermal and chemical stabilities under different operating conditions. [14][15][16][17][18] A few promising TMOs exhibit spinel structures, especially cobalt oxide, because Co in its d 7 state with unpaired electrons enhances the activation and polarization of media and the presence of different valences encourage electron transfer during ORR, OER, and HER. Similarly, manganese oxides are inexpensive and abundant materials that promote natural OER in plants, as well as the desired four-electron pathway toward ORR; however, the poor electronic conductivity of manganese oxides limits their electrocatalytic activity. To overcome these limitations, manganese oxide can be combined with cobalt as a co-metal in the spinel structure. Further, increasing the surface area and amounts of Mn 3+ and Mn 2+ can considerably enhance the The integration of energy conversion and storage systems such as electrochemical water splitting (EWS) and rechargeable zinc-air battery (ZAB) is on the vision to provide a sustainable future with green energy resources. Herein, a unique strategy for decorating 3D tetragonal CoMn 2 O 4 on carbon cloth (CMO-U@CC) via a facile one-pot in situ hydrothermal process, is reported. The highly exposed morphology of 3D tetragons enhances the electrocatalytic activity of CMO-U@CC. This is the first demonstration of such a bifunctional activity of CMO-U@CC in an EWS system; it achieves a nominal cell voltage of 1.610 ...

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Section: Aqueous Rechargeable Zinc-air Battery-driven Electrochemical Water Splittingsupporting

confidence: 64%

In Situ Grown CoMn₂O₄ 3D‐Tetragons on Carbon Cloth: Flexible Electrodes for Efficient Rechargeable Zinc–Air Battery Powered Water Splitting Systems

Janani

Surendran

Choi

et al. 2021

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“…It is found that the Co 3+ /Co 2+ ratio of LSCFO (1.50) is larger than those of LCO (0.84), LCFO (1.11), and LSCO (0.90). Previous studies showed that the ratio of Co 3+ to Co 2+ can act as the descriptor of the catalytic activity toward OER. ,, The larger ratio of Co 3+ to Co 2+ implies the better catalytic activity toward OER. Therefore, LSCFO is believed to exhibit the superior catalytic activity toward OER.…”

Section: Resultsmentioning

confidence: 99%

Adjusting the Covalency of Metal–Oxygen Bonds in LaCoO₃ by Sr and Fe Cation Codoping to Achieve Highly Efficient Electrocatalysts for Aprotic Lithium–Oxygen Batteries

Zheng

Chen

et al. 2021

ACS Appl. Mater. Interfaces

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Developing high-efficiency dual-functional catalysts to promote oxygen electrode reactions is critical for achieving high-performance aprotic lithium–oxygen (Li–O2) batteries. Herein, Sr and Fe cation-codoped LaCoO3 perovskite (La0.8Sr0.2Co0.8Fe0.2O3−σ, LSCFO) porous nanoparticles are fabricated as promising electrocatalysts for Li–O2 cells. The results demonstrate that the LSCFO-based Li–O2 batteries exhibit an extremely low overpotential of 0.32 V, ultrahigh specific capacity of 26 833 mA h g–1, and superior long-term cycling stability (200 cycles at 300 mA g–1). These prominent performances can be partially attributed to the existence of abundant coordination unsaturated sites caused by oxygen vacancies in LSCFO. Most importantly, density functional theory (DFT) calculations reveal that codoping of Sr and Fe cations in LaCoO3 results in the increased covalency of Co 3d–O 2p bonds and the transition of Co3+ from an ordinary low-spin state to an intermediate-spin state, eventually resulting in the transformation from nonconductor LCO to metallic LSCFO. In addition, based on the theoretical calculations, it is found that the inherent adsorption capability of LSCFO toward the LiO2 intermediate is reduced due to the increased covalency of Co 3d–O 2p bonds, leading to the formation of large granule-like Li2O2, which can be effectively decomposed on the LSCFO surface during the charging process. Notably, this work demonstrates a unique insight into the design of advanced perovskite oxide catalysts via adjusting the covalency of transition-metal–oxygen bonds for high-performance metal–air batteries.

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“…Conversely, if the e g orbital occupation is less than 1, the strong bonding between the catalyst and the adsorbate can poison the catalyst by hindering the desorption process and reducing the number of available binding sites. A correlation between activity and e g orbital filling has been suggested for some HER catalysts as well. , However, in many cases, assignment of the e g orbital occupancy has been done by electron count and based on the assumption of a certain spin state. ,,,, …”

Section: Resultsmentioning

confidence: 99%

“…A correlation between activity and e g orbital filling has been suggested for some HER catalysts as well. 76,77 However, in many cases, assignment of the e g orbital occupancy has been done by electron count and based on the assumption of a certain spin state. 1,13,73,76,77 We used DFT calculations to investigate the electronic structure and identify descriptors that led to the enhanced electrocatalytic activity of CaSrFe 0.75 Co 0.75 Mn 0.5 O 6−δ (CSFCM).…”

Section: Resultsmentioning

confidence: 99%

“…76,77 However, in many cases, assignment of the e g orbital occupancy has been done by electron count and based on the assumption of a certain spin state. 1,13,73,76,77 We used DFT calculations to investigate the electronic structure and identify descriptors that led to the enhanced electrocatalytic activity of CaSrFe 0.75 Co 0.75 Mn 0.5 O 6−δ (CSFCM). We also calculated the electronic structure of two other compositions with lower and higher Fe/Co contents, n a m e l y , C a S r F e 0 .…”

Section: Resultsmentioning

confidence: 99%

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Sustainable Oxide Electrocatalyst for Hydrogen- and Oxygen-Evolution Reactions

et al. 2021

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An electrocatalyst for water splitting based on earth-abundant metals is reported. This perovskite–oxide catalyst, CaSrFe0.75Co0.75Mn0.5O6−δ (CSFCM), is examined using both experimental and computational methods. It demonstrates a combination of properties, which include (a) very high activity for the oxygen-evolution reaction with an overpotential of η = 0.19 V at 10 mA/cm2, (b) high stability over 1000 cycles of catalysis, (c) the ability to catalyze the hydrogen-evolution reaction effectively in both acidic and basic conditions, and (d) catalytic activity as a single-phase bulk material without the need for any additional processing, multicomponent composite preparation, or nanofabrication. Therefore, the catalytic activity of CSFCM is intrinsic, making it a good benchmark compound for future studies of electrocatalytic parameters. This work also highlights the impact of systematic structural design on electrocatalytic activity. Results from density functional theory calculations indicate that in addition to an optimal e g occupancy of ∼1, an additional descriptor, i.e., maximizing the number of free e g carriers, correlates with the electrocatalytic activity.

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Enhancing oxygen and hydrogen evolution activities of perovskite oxide LaCoO₃via effective doping of platinum

Abstract: Among the perovskite LaCo1−xPtxO3−δ catalysts, LaCo0.94Pt0.06O3−δ proved best for catalyzing OER/HER, with η = 454/294 mV, which might be attributed to LCP6 having the eg orbital filling of Co closest to 1.2.

Cited by 41 publications

References 44 publications

In Situ Grown CoMn₂O₄ 3D‐Tetragons on Carbon Cloth: Flexible Electrodes for Efficient Rechargeable Zinc–Air Battery Powered Water Splitting Systems

In Situ Grown CoMn₂O₄ 3D‐Tetragons on Carbon Cloth: Flexible Electrodes for Efficient Rechargeable Zinc–Air Battery Powered Water Splitting Systems

Adjusting the Covalency of Metal–Oxygen Bonds in LaCoO₃ by Sr and Fe Cation Codoping to Achieve Highly Efficient Electrocatalysts for Aprotic Lithium–Oxygen Batteries

Sustainable Oxide Electrocatalyst for Hydrogen- and Oxygen-Evolution Reactions

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Enhancing oxygen and hydrogen evolution activities of perovskite oxide LaCoO3via effective doping of platinum

Abstract: Among the perovskite LaCo1−xPtxO3−δ catalysts, LaCo0.94Pt0.06O3−δ proved best for catalyzing OER/HER, with η = 454/294 mV, which might be attributed to LCP6 having the eg orbital filling of Co closest to 1.2.

Cited by 41 publications

References 44 publications

In Situ Grown CoMn2O4 3D‐Tetragons on Carbon Cloth: Flexible Electrodes for Efficient Rechargeable Zinc–Air Battery Powered Water Splitting Systems

In Situ Grown CoMn2O4 3D‐Tetragons on Carbon Cloth: Flexible Electrodes for Efficient Rechargeable Zinc–Air Battery Powered Water Splitting Systems

Adjusting the Covalency of Metal–Oxygen Bonds in LaCoO3 by Sr and Fe Cation Codoping to Achieve Highly Efficient Electrocatalysts for Aprotic Lithium–Oxygen Batteries

Sustainable Oxide Electrocatalyst for Hydrogen- and Oxygen-Evolution Reactions

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Enhancing oxygen and hydrogen evolution activities of perovskite oxide LaCoO₃via effective doping of platinum

In Situ Grown CoMn₂O₄ 3D‐Tetragons on Carbon Cloth: Flexible Electrodes for Efficient Rechargeable Zinc–Air Battery Powered Water Splitting Systems

In Situ Grown CoMn₂O₄ 3D‐Tetragons on Carbon Cloth: Flexible Electrodes for Efficient Rechargeable Zinc–Air Battery Powered Water Splitting Systems

Adjusting the Covalency of Metal–Oxygen Bonds in LaCoO₃ by Sr and Fe Cation Codoping to Achieve Highly Efficient Electrocatalysts for Aprotic Lithium–Oxygen Batteries