Carbons

Kinoshita, Kimio

doi:10.1002/9783527637188.ch10

Cited by 4 publications

(3 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although adding carbon to oxygen electrodes can be advantageous, carbon has stability issues in the cathodic operating conductions of real fuel cells . In addition, for any bifunctional applications, where the catalyst is subjected to ORR and OER potentials, carbon oxidation is even more significant . Therefore, it is of interest to develop perovskite electrodes without carbon or with a more stable conductive additive.…”

Section: Reaction Mechanismsmentioning

confidence: 99%

Perovskite Oxide Based Electrodes for the Oxygen Reduction and Evolution Reactions: The Underlying Mechanism

2021

View full text Add to dashboard Cite

One hindrance to the development of fuel cells and electrolyzers are the oxygen electrodes, which suffer from high overpotentials and slow kinetics. Perovskite oxides have been shown to be promising oxygen electrode catalysts because of their low cost, flexibility, and tailorable properties. In order to improve perovskite catalysts for the oxygen reduction (ORR) and oxygen evolution (OER) reactions, a better understanding of their reaction mechanisms is needed. This Perspective aims to inform researchers of the current proposed reaction mechanisms for ORR and OER on perovskites and perovskite/carbon composites in order to guide future catalyst development. Additionally, important experimental practices will be recommended. A recent development for OER is the lattice oxygen evolution reaction, which is a possible addition to the conventional four consecutive proton-coupled electron transfer mechanism. Carbon additives are consistently added to perovskites to enhance conductivity and ORR/OER activity. However, carbon plays an active role in ORR, and there is evidence of a synergistic relationship between perovskite and carbon in perovskite/carbon composites.

show abstract

Section: Reaction Mechanismsmentioning

confidence: 99%

Perovskite Oxide Based Electrodes for the Oxygen Reduction and Evolution Reactions: The Underlying Mechanism

2021

View full text Add to dashboard Cite

show abstract

“…Unfortunately, carbon-based air electrodes are susceptible to rapid corrosion at the high oxidizing potentials experienced at the air electrode during charging (OER) of a zinc–air battery. − The standard potential of carbon oxidation in alkaline electrolyte (pH of 14) is −0.78 V vs SHE (0.48 V vs Zn/ZnO), which is much lower than the ORR/OER equilibrium potential (0.40 V vs SHE, 1.66 V vs Zn/ZnO). , Therefore, although graphitization of carbon improves its corrosion resistance, ,,− corrosion is thermodynamically favored even at the open circuit voltage of zinc–air batteries. Also, the formation of carbonate (CO 3 2– ) ions from carbon corrosion can combine with CO 2 poisoning from the outside atmosphere to hasten the precipitation of K 2 CO 3 in the air electrode pores, which can block catalyst sites and limit oxygen diffusion .…”

Section: Introductionmentioning

confidence: 99%

New Interpretation of the Performance of Nickel-Based Air Electrodes for Rechargeable Zinc–Air Batteries

et al. 2018

View full text Add to dashboard Cite

Rechargeable zinc−air batteries with high energy density, cycle life, and calendar life require corrosion-resistant support materials in the air electrode. Nickel-based air electrodes have shown promise in this regard as a substitute for conventional carbon-based air electrodes, but their performance in zinc−air batteries has not been studied in-depth. Specifically, the effect of the nickel (oxy)hydroxide passivating film on the electrode's catalytic performance and durability requires investigation. To fill this research gap, a method involving electrochemical estimation of the nickel (oxy)hydroxide film capacity was used to link the growth of the film to performance losses experienced on the air electrode after battery cycling. The main cause of voltage loss was the nickel (oxy)hydroxide film growing overtop of and inside the catalyst-coated nickel aggregates. This resulted in significant activation and mass transfer losses, where the latter losses were caused by the film growing overtop of the catalyst and accounted for at least 65% of the total voltage degradation at 10 mA cm −2 . Potential modifications to the electrode structure which could mitigate these voltage losses are discussed, including reducing the nickel particle aggregate size, using high-aspect ratio catalysts, and physically separating the catalyst and nickel particles with nonfilm-forming conductive additives.

show abstract

“…The oxidizing agents rise the oxidation level of carbon black which increases more acidity in their structures due to generation of oxygen functional groups [1]. Moreover, a rising of the oxygen functional groups decreases their electrical conductivity because they generate defects and vacancies inside the layer of graphite and expands the intercalation of crystals of graphite-like structure [ 17,18] .…”

Section: Carbon Blackmentioning

confidence: 99%

Parameters affecting morphology and chemical structure of carbon black synthesized by acetylene black process

Laowtaweerungruang

View full text Add to dashboard Cite

Acetylene black is widely used as a composite in various applications such as electronic devices, electrode materials, pigments, polymer composites, and catalyst supports. Not only its unique property of electrical conductivity but also other properties are required for various applications. The properties of acetylene black mostly depend on its morphological and chemical structures which can be controlled by synthesis parameters or modified by pre- and post-treatment. In this work, we observe the effect of temperature, acetylene concentration, and residence time on morphological and chemical structures of synthesized acetylene black through thermal decomposition process. The results show that, at an initial state, heat energy accelerates the nucleation rate, which provides smaller particles in both of primary and aggregate forms, and induces the reaction over the heated area. Higher temperature condition contributes to the sintering between crystal edges (La) and to the elimination of organic functional groups which totally disappear over 1100 °C. Higher concentration of feedstock generates higher saturated system which drives the collision between molecules and particles. It also induces the nucleation as the effect of temperature. Then, active collisions of particles push the larger size of aggregate structure. The long residence time also expands the growth period of carbon particles which increases the sizes of primary particles, aggregates, and La. In addition, synthesis temperature acts as a key parameter in the formation of acetylene black. The acetylene concentration and residence time slightly affect the acetylene black structure.

show abstract

Carbons

Cited by 4 publications

References 36 publications

Perovskite Oxide Based Electrodes for the Oxygen Reduction and Evolution Reactions: The Underlying Mechanism

Perovskite Oxide Based Electrodes for the Oxygen Reduction and Evolution Reactions: The Underlying Mechanism

New Interpretation of the Performance of Nickel-Based Air Electrodes for Rechargeable Zinc–Air Batteries

Parameters affecting morphology and chemical structure of carbon black synthesized by acetylene black process

Contact Info

Product

Resources

About