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Carbon-based electrocatalysts for advanced energy conversion and storage.

Zhang J, Xia Z, Dai L - Sci Adv (2015)

Bottom Line: Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) play curial roles in electrochemical energy conversion and storage, including fuel cells and metal-air batteries.Having rich multidimensional nanoarchitectures [for example, zero-dimensional (0D) fullerenes, 1D carbon nanotubes, 2D graphene, and 3D graphite] with tunable electronic and surface characteristics, various carbon nanomaterials have been demonstrated to act as efficient metal-free electrocatalysts for ORR and OER in fuel cells and batteries.We present a critical review on the recent advances in carbon-based metal-free catalysts for fuel cells and metal-air batteries, and discuss the perspectives and challenges in this rapidly developing field of practical significance.

View Article: PubMed Central - PubMed

Affiliation: Center of Advanced Science and Engineering for Carbon (Case4Carbon), Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.

ABSTRACT
Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) play curial roles in electrochemical energy conversion and storage, including fuel cells and metal-air batteries. Having rich multidimensional nanoarchitectures [for example, zero-dimensional (0D) fullerenes, 1D carbon nanotubes, 2D graphene, and 3D graphite] with tunable electronic and surface characteristics, various carbon nanomaterials have been demonstrated to act as efficient metal-free electrocatalysts for ORR and OER in fuel cells and batteries. We present a critical review on the recent advances in carbon-based metal-free catalysts for fuel cells and metal-air batteries, and discuss the perspectives and challenges in this rapidly developing field of practical significance.

No MeSH data available.


Related in: MedlinePlus

Evaluation of electrocatalytic activities toward ORR and OER.(A) LSV curves of electrocatalysts in oxygen-saturated electrolyte with different rotating rates. (B) Oxygen reduction curves on the disc and ring electrodes of RRDE at 5 mV s−1 scan rate at 1600 rpm, respectively. (C) Exemplary OER currents of La1−xCaxCoO3 and LaCoO3 thin films on a glassy carbon electrode (GCE) in O2-saturated 0.1 M KOH at 10 mV s−1 scan rate at 1600 rpm, capacitance-corrected by taking an average of the positive and negative scans. The contributions from AB (acetylene black) and binder (Nafion) in the thin film and GCE are shown for comparison. (D) Evidence of O2 generated from Ba0.5Sr0.5Co0.8Fe0.2O3−d (BSCF) using RRDE measurements (schematic shown as an inset). The O2 gas generated from BSCF on a GCE disc (OER current given as idisc) is reduced at the Pt ring at a constant potential of 0.4 V versus reversible hydrogen electrode (RHE). The collecting efficiency of RRED is 0.2. [From J. Suntivich, K. J. May, H. A. Gasteiger, J. B. Goodenough, Y. Shao-Horn, A perovskite oxide optimized for oxygen evolution catalysis from molecular orbital principles. Science334, 1383–1385 (2011). Reprinted with permission from AAAS.]
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Figure 1: Evaluation of electrocatalytic activities toward ORR and OER.(A) LSV curves of electrocatalysts in oxygen-saturated electrolyte with different rotating rates. (B) Oxygen reduction curves on the disc and ring electrodes of RRDE at 5 mV s−1 scan rate at 1600 rpm, respectively. (C) Exemplary OER currents of La1−xCaxCoO3 and LaCoO3 thin films on a glassy carbon electrode (GCE) in O2-saturated 0.1 M KOH at 10 mV s−1 scan rate at 1600 rpm, capacitance-corrected by taking an average of the positive and negative scans. The contributions from AB (acetylene black) and binder (Nafion) in the thin film and GCE are shown for comparison. (D) Evidence of O2 generated from Ba0.5Sr0.5Co0.8Fe0.2O3−d (BSCF) using RRDE measurements (schematic shown as an inset). The O2 gas generated from BSCF on a GCE disc (OER current given as idisc) is reduced at the Pt ring at a constant potential of 0.4 V versus reversible hydrogen electrode (RHE). The collecting efficiency of RRED is 0.2. [From J. Suntivich, K. J. May, H. A. Gasteiger, J. B. Goodenough, Y. Shao-Horn, A perovskite oxide optimized for oxygen evolution catalysis from molecular orbital principles. Science334, 1383–1385 (2011). Reprinted with permission from AAAS.]

Mentions: Figure 1A represents the typical LSV curves of ORR tested on RDE at various rotating speeds, showing an increased Jd with increasing rotating speeds due to the enhanced oxygen diffusion to and reduction at the electrode surface. At high overpotentials, the oxygen reduction is so fast that a limiting plateau is achieved (Fig. 1A). This current plateau would be associated with the distribution of the electrocatalytic sites on the electrode surfaces (41). Typically, the uniform distribution of active sites leads to a fine current plateau. In contrast, the current plateau is more inclined if the distribution of active sites is less uniform and the electrocatalytic reaction is slower. n and Jk can be obtained by Koutecky-Levich plots, in which the diffusion limitation can be eliminated. Alternatively, RRDE can be used to determine the kinetics and mechanism of ORR. This technology can quantitatively evaluate the molar proportion of produced H2O2/HO2− on the ring electrode (platinum or gold, Fig. 1B). The disc and ring currents (ID and IR, respectively) are recorded as a function of the disc electrode potential (Fig. 1B). Taking into account that the total disc current, ID, is the sum of the O2 reduction currents to water, , and intermediate (H2O2), , and using the collection efficiency (N), we have Eq. 3:


Carbon-based electrocatalysts for advanced energy conversion and storage.

Zhang J, Xia Z, Dai L - Sci Adv (2015)

Evaluation of electrocatalytic activities toward ORR and OER.(A) LSV curves of electrocatalysts in oxygen-saturated electrolyte with different rotating rates. (B) Oxygen reduction curves on the disc and ring electrodes of RRDE at 5 mV s−1 scan rate at 1600 rpm, respectively. (C) Exemplary OER currents of La1−xCaxCoO3 and LaCoO3 thin films on a glassy carbon electrode (GCE) in O2-saturated 0.1 M KOH at 10 mV s−1 scan rate at 1600 rpm, capacitance-corrected by taking an average of the positive and negative scans. The contributions from AB (acetylene black) and binder (Nafion) in the thin film and GCE are shown for comparison. (D) Evidence of O2 generated from Ba0.5Sr0.5Co0.8Fe0.2O3−d (BSCF) using RRDE measurements (schematic shown as an inset). The O2 gas generated from BSCF on a GCE disc (OER current given as idisc) is reduced at the Pt ring at a constant potential of 0.4 V versus reversible hydrogen electrode (RHE). The collecting efficiency of RRED is 0.2. [From J. Suntivich, K. J. May, H. A. Gasteiger, J. B. Goodenough, Y. Shao-Horn, A perovskite oxide optimized for oxygen evolution catalysis from molecular orbital principles. Science334, 1383–1385 (2011). Reprinted with permission from AAAS.]
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4643813&req=5

Figure 1: Evaluation of electrocatalytic activities toward ORR and OER.(A) LSV curves of electrocatalysts in oxygen-saturated electrolyte with different rotating rates. (B) Oxygen reduction curves on the disc and ring electrodes of RRDE at 5 mV s−1 scan rate at 1600 rpm, respectively. (C) Exemplary OER currents of La1−xCaxCoO3 and LaCoO3 thin films on a glassy carbon electrode (GCE) in O2-saturated 0.1 M KOH at 10 mV s−1 scan rate at 1600 rpm, capacitance-corrected by taking an average of the positive and negative scans. The contributions from AB (acetylene black) and binder (Nafion) in the thin film and GCE are shown for comparison. (D) Evidence of O2 generated from Ba0.5Sr0.5Co0.8Fe0.2O3−d (BSCF) using RRDE measurements (schematic shown as an inset). The O2 gas generated from BSCF on a GCE disc (OER current given as idisc) is reduced at the Pt ring at a constant potential of 0.4 V versus reversible hydrogen electrode (RHE). The collecting efficiency of RRED is 0.2. [From J. Suntivich, K. J. May, H. A. Gasteiger, J. B. Goodenough, Y. Shao-Horn, A perovskite oxide optimized for oxygen evolution catalysis from molecular orbital principles. Science334, 1383–1385 (2011). Reprinted with permission from AAAS.]
Mentions: Figure 1A represents the typical LSV curves of ORR tested on RDE at various rotating speeds, showing an increased Jd with increasing rotating speeds due to the enhanced oxygen diffusion to and reduction at the electrode surface. At high overpotentials, the oxygen reduction is so fast that a limiting plateau is achieved (Fig. 1A). This current plateau would be associated with the distribution of the electrocatalytic sites on the electrode surfaces (41). Typically, the uniform distribution of active sites leads to a fine current plateau. In contrast, the current plateau is more inclined if the distribution of active sites is less uniform and the electrocatalytic reaction is slower. n and Jk can be obtained by Koutecky-Levich plots, in which the diffusion limitation can be eliminated. Alternatively, RRDE can be used to determine the kinetics and mechanism of ORR. This technology can quantitatively evaluate the molar proportion of produced H2O2/HO2− on the ring electrode (platinum or gold, Fig. 1B). The disc and ring currents (ID and IR, respectively) are recorded as a function of the disc electrode potential (Fig. 1B). Taking into account that the total disc current, ID, is the sum of the O2 reduction currents to water, , and intermediate (H2O2), , and using the collection efficiency (N), we have Eq. 3:

Bottom Line: Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) play curial roles in electrochemical energy conversion and storage, including fuel cells and metal-air batteries.Having rich multidimensional nanoarchitectures [for example, zero-dimensional (0D) fullerenes, 1D carbon nanotubes, 2D graphene, and 3D graphite] with tunable electronic and surface characteristics, various carbon nanomaterials have been demonstrated to act as efficient metal-free electrocatalysts for ORR and OER in fuel cells and batteries.We present a critical review on the recent advances in carbon-based metal-free catalysts for fuel cells and metal-air batteries, and discuss the perspectives and challenges in this rapidly developing field of practical significance.

View Article: PubMed Central - PubMed

Affiliation: Center of Advanced Science and Engineering for Carbon (Case4Carbon), Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.

ABSTRACT
Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) play curial roles in electrochemical energy conversion and storage, including fuel cells and metal-air batteries. Having rich multidimensional nanoarchitectures [for example, zero-dimensional (0D) fullerenes, 1D carbon nanotubes, 2D graphene, and 3D graphite] with tunable electronic and surface characteristics, various carbon nanomaterials have been demonstrated to act as efficient metal-free electrocatalysts for ORR and OER in fuel cells and batteries. We present a critical review on the recent advances in carbon-based metal-free catalysts for fuel cells and metal-air batteries, and discuss the perspectives and challenges in this rapidly developing field of practical significance.

No MeSH data available.


Related in: MedlinePlus