Core–Shell-Structured Low-Platinum Electrocatalysts for Fuel Cell Applications

Wang, Rongfang; Wang, Hui; Luo, Fan; Liao, Shijun

doi:10.1007/s41918-018-0013-0

Cited by 83 publications

(53 citation statements)

References 602 publications

(630 reference statements)

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“…In electrochemical energy storage and conversion devices such as fuel cell and metal-air batteries, the applications of electrocatalysts for cathode oxygen reduction reaction (ORR) are of paramount importance. 1,2 As recognized, ORR in aqueous solutions occurs mainly through two pathways: one is the direct 4-electron reduction from O 2 to water (H 2 O), and the other is the 2-electron reduction from O 2 to hydrogen peroxide (H 2 O 2 ). In general, the ORR kinetics on electrodes is sluggish.…”

Section: Introductionmentioning

confidence: 99%

Nanoparticles of Fe2O3 and Co3O4 as Efficient Electrocatalysts for Oxygen Reduction Reaction in Acid Medium

Alves

Santos

Viégas

et al. 2019

J. Braz. Chem. Soc.

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This paper presents a comparative study about the oxygen reduction reaction (ORR) catalyzed by nanoparticles of Fe 2 O 3 and Co 3 O 4 applied on the surface of glassy carbon electrodes (GCE). The nanoparticles were synthesized using the modified polymeric precursor method (Pechini). These two nanomaterials were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) techniques. The estimated average particle sizes were 21 and 31 nm for Fe 2 O 3 and Co 3 O 4 , respectively. Electrochemical impedance spectroscopy (EIS) showed that Fe 2 O 3 /GCE has lower charge transfer resistance than Co 3 O 4 /GCE. The surface electrochemistry of both Fe 2 O 3 /GCE and Co 3 O 4 /GCE was studied in the solution free of O 2 , and their corresponding reaction mechanisms were analyzed. The electrocatalytic ORR activities of these two catalysts were studied by cyclic voltammetry (CV) and rotating disk electrode (RDE) in acidic solution. The results obtained by RDE indicated that both Fe 2 O 3 /GCE and Co 3 O 4 /GCE can catalyze the ORR with a dominating 2-electron transfer process to produce H 2 O 2 , using a potential of −0.8 V. These kinetic results indicate that Fe 2 O 3 /GCE is more efficient than Co 3 O 4 /GCE in terms of ORR. Considering the low cost of these two non-noble metal catalysts, they may be used as viable alternatives for ORR electrocatalysts.

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Section: Introductionmentioning

confidence: 99%

Nanoparticles of Fe2O3 and Co3O4 as Efficient Electrocatalysts for Oxygen Reduction Reaction in Acid Medium

Alves

Santos

Viégas

et al. 2019

J. Braz. Chem. Soc.

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“…The theoretical voltage of the passive DFFC is 1.45 V, which greatly exceeds that of direct methanol fuel cells (1.21 V), direct ethanol fuel cells (1.14 V), and direct ethylene glycol fuel cells (1.09 V) . However, in fuel cells, the theoretical one is hardly achieved due to overpotentials in physical and chemical processes . First, the open‐circuit voltage (OCV) is not able to reach the theoretical value due to the poor reversibility of electrode reactions .…”

Section: Working Principle Of the Passive Dffcmentioning

confidence: 96%

“…9 However, in fuel cells, the theoretical one is hardly achieved due to overpotentials in physical and chemical processes. [8][9][10][11][12][13][14][15][16][17][18] First, the open-circuit voltage (OCV) is not able to reach the theoretical value due to the poor reversibility of electrode reactions. 38 Second, mixed potential is induced by the fuel crossover in the cathode, further lowering the cell voltage.…”

Section: Working Principle Of the Passive Dffcmentioning

confidence: 99%

“…The high operation cost of hydrogen limits the practical application of hydrogen fuel cells . For this reason, liquid fuels have gained more attention, primarily because of their high energy densities and easier‐operated characteristics . Among them, formate, mainly referring to sodium formate (HCOONa) or potassium formate (HCOOK) dissolved in an aqueous solution, has drawn increasing interest due to the following advantageous characteristics: (1) The theoretical voltage of direct formate fuel cells (DFFCs) running on oxygen is 1.45 V, which exceeds 1.21 V of direct methanol fuel cells, 1.14 V of direct ethanol fuel cells, and 1.09 V of direct ethylene glycol fuel cells; (2) solid formate salts are easily handled in storage and transport, and they have high melting points (253 °C of sodium formate and 167.5 °C of potassium formate) so that they are ready for extensive use; (3) the fuel solution can be easily formed via dissolving formate salts into water; (4) formate salts can be synthesized through photoelectrochemically reducing carbon dioxide, along with solar energy harvesting; (5) formate oxidation reaction (FOR) is facile in alkaline media; and (6) radically different from incomplete oxidation of ethanol producing acetic acid and water, formate can be fully oxidized producing water and carbon dioxide, resulting in high electron transfer rate and current efficiency .…”

Section: Introductionmentioning

confidence: 99%

“…[5][6][7] For this reason, liquid fuels have gained more attention, primarily because of their high energy densities and easier-operated characteristics. [8][9][10][11][12][13][14][15][16][17][18] Among them, formate, mainly referring to sodium formate (HCOONa) or potassium formate (HCOOK) dissolved in an aqueous solution, has drawn increasing interest due to the following advantageous characteristics: (1) The theoretical voltage of direct formate fuel cells (DFFCs) running on oxygen is 1.45 V, which exceeds 1.21 V of direct methanol fuel cells, 1.14 V of direct ethanol fuel cells, and 1.09 V of direct ethylene glycol fuel cells;…”

Section: Introductionmentioning

confidence: 99%

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Performance characteristics of a passive direct formate fuel cell

Pan

2019

Int J Energy Res

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Summary A passive direct formate fuel cell using ambient air is designed, fabricated, and tested. This fuel cell does not use any auxiliary devices such as pumps, gas compressors, and gas blowers. The simple and compact structure well fits the need of portable applications. In this fuel cell, a solution having formate and alkali is anode fuel, while ambient oxygen is used as cathode oxidant, and a cation exchange membrane serves as an ionic conductor between two electrodes. Our performance tests have shown that a peak power density of 16.6 mW cm−2 as well as an open‐circuit voltage of 0.97 V are achieved by the present fuel cell at 60 °C, when running on anode fuel containing 5.0 M sodium formate and 3.0 M sodium hydroxide. This performance is even 31.7% higher than that achieved by an active direct formate fuel cell reported in the open literature (12.6 mW cm−2), which also uses a cation exchange membrane. The effects of the operating parameters are also investigated, including the concentrations of fuel and alkali as well as the operating temperature. The fuel solution at low concentrations results in an inadequate local concentration of reactants, so that the anodic kinetics becomes sluggish. Although increasing the sodium hydroxide concentration enhances the anodic formate oxidation kinetics, too high concentration of sodium hydroxide leads to too many active sites being covered by hydroxide ions and thus adsorption and reaction of formate ions being limited. Moreover, too high concentration of sodium hydroxide or sodium formate also leads to the fuel solution being highly viscous, hindering the motion of various ions, as well as thus increasing both concentration loss and the ohmic loss. The compromise between benefits and the drawbacks of using high‐concentration reactants results in an optimal composition of the fuel solution, which contains 5.0 M sodium formate and 3.0 M sodium hydroxide. Furthermore, the present fuel cell delivers a voltage around 0.6 V for 20 hours at 4.0 mA cm−2.

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Toward Electrocatalytic Methanol Oxidation Reaction: Longstanding Debates and Emerging Catalysts

et al. 2023

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The study of direct methanol fuel cells (DMFCs) has lasted around 70 years, since the first investigation in the early 1950s. Though enormous effort has been devoted in this field, it is still far from commercialization. The methanol oxidation reaction (MOR), as a semi‐reaction of DMFCs, is the bottleneck reaction that restricts the overall performance of DMFCs. To date, there has been intense debate on the complex six‐electron reaction, but barely any reviews have systematically discussed this topic. To this end, the controversies and progress regarding the electrocatalytic mechanisms, performance evaluations as well as the design science toward MOR electrocatalysts are summarized. This review also provides a comprehensive introduction on the recent development of emerging MOR electrocatalysts with a focus on the innovation of the alloy, core–shell structure, heterostructure, and single‐atom catalysts. Finally, perspectives on the future outlook toward study of the mechanisms and design of electrocatalysts are provided.

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Core–Shell-Structured Low-Platinum Electrocatalysts for Fuel Cell Applications

Cited by 83 publications

References 602 publications

Nanoparticles of Fe2O3 and Co3O4 as Efficient Electrocatalysts for Oxygen Reduction Reaction in Acid Medium

Nanoparticles of Fe2O3 and Co3O4 as Efficient Electrocatalysts for Oxygen Reduction Reaction in Acid Medium

Performance characteristics of a passive direct formate fuel cell

Toward Electrocatalytic Methanol Oxidation Reaction: Longstanding Debates and Emerging Catalysts

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