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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

Polarization curve of PEMFC.The typical polarization curve describes the relationship between cell voltage and current density used to evaluate cell performance. The various losses are shown in the same figure, indicating different overpotential sources. [From V. Ramani, H. R. Kunz, J. M. Fenton, The polymer electrolyte fuel cell. Electrochem. Soc. Interface13, 17 (2004). Reprinted with permission from the Electrochemical Society.]
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Figure 2: Polarization curve of PEMFC.The typical polarization curve describes the relationship between cell voltage and current density used to evaluate cell performance. The various losses are shown in the same figure, indicating different overpotential sources. [From V. Ramani, H. R. Kunz, J. M. Fenton, The polymer electrolyte fuel cell. Electrochem. Soc. Interface13, 17 (2004). Reprinted with permission from the Electrochemical Society.]

Mentions: A fuel cell is an electrochemical device to directly convert chemical energy into electricity by oxidizing fuels (for example, hydrogen, methanol, ethanol, and formic acid) at the anode and reducing oxygen at the cathode. Figure 2 shows the typical steady-state polarization curve of PEMFCs (45), which describes the relationship between the electrode potential and the current density for evaluating both ORR and fuel cell performance. The criteria to evaluate a polarization curve depend on its application (46). It can be seen in Fig. 2 that the fuel cell voltage is significantly deviated from the theoretical potential (also called reversible standard potential, 1.23 V) (47). The loss could be attributed to electrode kinetics (electron transfer overpotential), slow mass transport (diffusion overpotential), and slow chemical reactions coupled to the electron transfer (reaction overpotential). We note that the sluggish ORR is about six or more orders of magnitude slower than the hydrogen oxidation reaction in a PEMFC (48). Thus, ORR has a limiting factor to the cell performance, which requires a platinum catalyst (see above). Because of the high cost and poor durability intrinsically associated with platinum catalysts, the development of nonprecious metal and metal-free catalysts with high ORR activities has become the major focus of fuel cell research (15, 49).


Carbon-based electrocatalysts for advanced energy conversion and storage.

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

Polarization curve of PEMFC.The typical polarization curve describes the relationship between cell voltage and current density used to evaluate cell performance. The various losses are shown in the same figure, indicating different overpotential sources. [From V. Ramani, H. R. Kunz, J. M. Fenton, The polymer electrolyte fuel cell. Electrochem. Soc. Interface13, 17 (2004). Reprinted with permission from the Electrochemical Society.]
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: Polarization curve of PEMFC.The typical polarization curve describes the relationship between cell voltage and current density used to evaluate cell performance. The various losses are shown in the same figure, indicating different overpotential sources. [From V. Ramani, H. R. Kunz, J. M. Fenton, The polymer electrolyte fuel cell. Electrochem. Soc. Interface13, 17 (2004). Reprinted with permission from the Electrochemical Society.]
Mentions: A fuel cell is an electrochemical device to directly convert chemical energy into electricity by oxidizing fuels (for example, hydrogen, methanol, ethanol, and formic acid) at the anode and reducing oxygen at the cathode. Figure 2 shows the typical steady-state polarization curve of PEMFCs (45), which describes the relationship between the electrode potential and the current density for evaluating both ORR and fuel cell performance. The criteria to evaluate a polarization curve depend on its application (46). It can be seen in Fig. 2 that the fuel cell voltage is significantly deviated from the theoretical potential (also called reversible standard potential, 1.23 V) (47). The loss could be attributed to electrode kinetics (electron transfer overpotential), slow mass transport (diffusion overpotential), and slow chemical reactions coupled to the electron transfer (reaction overpotential). We note that the sluggish ORR is about six or more orders of magnitude slower than the hydrogen oxidation reaction in a PEMFC (48). Thus, ORR has a limiting factor to the cell performance, which requires a platinum catalyst (see above). Because of the high cost and poor durability intrinsically associated with platinum catalysts, the development of nonprecious metal and metal-free catalysts with high ORR activities has become the major focus of fuel cell research (15, 49).

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