PEM fuel cell electrocatalysts based on transition metal macrocyclic compounds

Liu, Yuyu; Yue, Xiuping; Li, Kaixi; Qiao, Jinli; Wilkinson, David P.; Zhang, Jiujun

doi:10.1016/j.ccr.2016.02.002

Cited by 113 publications

(70 citation statements)

References 138 publications

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“…The standard redox potential of the four‐electron reduction of O 2 with four protons to water under the standard conditions of aqueous acid with unit activity (pH 0), an oxygen pressure of 1 atm and at 25 °C is 1.229 V referenced to the standard hydrogen electrode (SHE) [Eq. ]

true normalO_{2} + 4 normale^{-} + 4 H^{+} \to 2 normalH_{2} normalO E_{0} = 1.229 normalV vs . SHE

…”

Section: Introductionmentioning

confidence: 99%

Mechanisms of Two‐Electron versus Four‐Electron Reduction of Dioxygen Catalyzed by Earth‐Abundant Metal Complexes

2017

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The two‐electron reduction of dioxygen with two protons produces hydrogen peroxide, which is directly used as a liquid fuel in hydrogen peroxide fuel cells, whereas the four‐electron reduction of dioxygen is combined with the two‐electron oxidation of hydrogen in hydrogen fuel cells. Platinum (Pt)‐based nanocomposites are the most efficient commercial electrocatalysts for the oxygen reduction reaction (ORR). However, the poor stability, scarcity and high cost of these Pt‐based oxygen electrocatalysts are major barriers for the large‐scale implementation of fuel cell technologies. Replacing noble metal‐based electrocatalysts with highly efficient and inexpensive earth‐abundant metal‐based oxygen electrocatalysts has been of critical importance for practical applications. To develop efficient catalysts for the two‐electron and four‐electron reduction of dioxygen, it is crucially important to clarify the catalytic mechanisms of two‐electron/two‐proton versus four‐electron/four‐proton reduction of dioxygen with earth‐abundant metal complexes. This review focused on the factors that control the two‐electron/two‐proton versus four‐electron/four‐proton reduction of dioxygen by electron donors (one electron reductants) such as ferrocene, catalyzed by earth‐abundant metal complexes such as iron, cobalt, copper, manganese and nickel complexes in the homogeneous phase, by detecting catalytic intermediates, which determine the catalytic pathways of the two‐electron versus four‐electron reduction of dioxygen. The electrocatalytic two‐electron or/and four‐electron reduction of dioxygen with earth‐abundant metal complexes and metal oxides has also been discussed in relation with the homogeneous catalysis.

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true normalO_{2} + 4 normale^{-} + 4 H^{+} \to 2 normalH_{2} normalO E_{0} = 1.229 normalV vs . SHE

…”

Section: Introductionmentioning

confidence: 99%

Mechanisms of Two‐Electron versus Four‐Electron Reduction of Dioxygen Catalyzed by Earth‐Abundant Metal Complexes

2017

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“…Their result indicate that even if Fe‐N 4 units undergo a series of ligand and structural change after 800 °C heat treatment, the Fe‐N 4 moiety still exist and be considered as the active site for ORR (Figure b) . The special electronic structure of the TM centers facilitates the adsorption of O 2 molecule and the break of O−O bond ,,,…”

Section: Origin Configuration Characterization and Catalytic Mechanmentioning

confidence: 99%

“…The Origin of TM-N 4 ORR-effective TM-N 4 site can be traced back to the metal chelates with N 4 -types, [53] such as cobalt phthalocyanine (CoPc), [12] iron phthalocyanine (FePc), cobalt dibenzotetraazaannulene (CoTAA) [54] and iron porphyrin (FePP). [40] TM-N 4 is known as the basic structural units of these N 4 -chelates (e. g. Figure 2a).…”

Section: Origin Configuration Characterization and Catalytic Mechanmentioning

confidence: 99%

“…electronic structure of the TM centers facilitates the adsorption of O 2 molecule and the break of OÀ O bond. [7,40,53,58]…”

Section: Origin Configuration Characterization and Catalytic Mechanmentioning

confidence: 99%

“…Various TM-N-C catalysts have been developed along with TM macrocyclic compounds. [7,13,53] Several configurations of TM-N 4 active site were proposed simultaneously. First is the TM-N 4 type macrocyclic compounds themselves as shown in Figure 2a.…”

Section: Configuration Of Tm-n 4 Active Site and Architecture Of Tm-nmentioning

confidence: 99%

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Transition Metal‐Nitrogen‐Carbon Active Site for Oxygen Reduction Electrocatalysis: Beyond the Fascinations of TM‐N₄

Zhang

Zheng

2018

ChemCatChem

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Low cost transition metal‐nitrogen‐carbon (TM‐N‐C) catalysts hold excellent electrocatalytic activity and stability for oxygen reduction reaction (ORR), and have been considered as the most promising alternative to commercial Pt/C. TM‐N4, once identified as one potential active site for ORR, are brought to the spotlight by several single atom TM‐N‐C catalysts recently. However, it remains ambiguous whether this active site exists and is active for ORR because of the controversial analysis about similar TM‐N‐C catalysts by different groups. Herein, we elucidated the origin, architecture, characterization methods and possible catalytic mechanism of TM‐N4 active site. Some recent cases about single atom TM‐N‐C catalysts with TM‐N4 active site were comprehensively reviewed. Thus, some derived perspectives were presented. Undoubtedly, TM‐N4 enables being qualified as one possible type of active site for ORR. However, a general acceptance may mislead for clarifying, as confirmation of the metal‐centered coordination environment requires for more advanced technologies and strategies.

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polymer electrolyte membrane fuel cells

Brosy¹

2020

Catalysis From a to Z

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PEM fuel cell electrocatalysts based on transition metal macrocyclic compounds

Cited by 113 publications

References 138 publications

Mechanisms of Two‐Electron versus Four‐Electron Reduction of Dioxygen Catalyzed by Earth‐Abundant Metal Complexes

Mechanisms of Two‐Electron versus Four‐Electron Reduction of Dioxygen Catalyzed by Earth‐Abundant Metal Complexes

Transition Metal‐Nitrogen‐Carbon Active Site for Oxygen Reduction Electrocatalysis: Beyond the Fascinations of TM‐N₄

polymer electrolyte membrane fuel cells

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PEM fuel cell electrocatalysts based on transition metal macrocyclic compounds

Cited by 113 publications

References 138 publications

Mechanisms of Two‐Electron versus Four‐Electron Reduction of Dioxygen Catalyzed by Earth‐Abundant Metal Complexes

Mechanisms of Two‐Electron versus Four‐Electron Reduction of Dioxygen Catalyzed by Earth‐Abundant Metal Complexes

Transition Metal‐Nitrogen‐Carbon Active Site for Oxygen Reduction Electrocatalysis: Beyond the Fascinations of TM‐N4

polymer electrolyte membrane fuel cells

Contact Info

Product

Resources

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Transition Metal‐Nitrogen‐Carbon Active Site for Oxygen Reduction Electrocatalysis: Beyond the Fascinations of TM‐N₄