Crumpled rGO-supported Pt-Ir bifunctional catalyst prepared by spray pyrolysis for unitized regenerative fuel cells

Kim, In Gyeom; Nah, In Wook; Oh, In‐Hwan; Park, Sehkyu

doi:10.1016/j.jpowsour.2017.08.015

Cited by 43 publications

(45 citation statements)

References 56 publications

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“…Notably, the pyridinic and graphitic nitrogen, considered to be the most efficient active sites of all the nitrogen species in CoO/NC are able to not only enhance the initial chemical adsorption of oxygen on the catalyst surface but increase the number of catalytically active sites for ORR . Moreover, the interaction between Co and N in the Co−N bonds (399.1 eV) increases active sites and improves the ORR performance due to the electron density redistribution . Accordingly, the total amount of N in CoO/NC2 was estimated to be 2.56 at.% by XPS analysis.…”

Section: Resultssupporting

confidence: 90%

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Enhanced Oxygen Reduction Stability and Activity by Co and N (or O) Interaction in CoO on N‐Doped Carbon Prepared through Spray Pyrolysis

2018

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Although the development of a highly active and cost‐effective electrocatalyst for the oxygen reduction reaction (ORR) is necessary, it is a challenging issue for commercially viable energy conversion applications such as fuel cells or metal‐air batteries. In this study, we synthesize nitrogen‐doped, carbon‐supported CoO catalysts (denoted as CoO/NCs) with high stability and activity. The CoO/NC is prepared by one‐pot spray pyrolysis, which is simple and has an easily scalable synthetic route. In an effort to find a better catalyst composition for ORR activity, several catalysts are synthesized by controlling the concentrations of the solutions that contain carbon, urea as the nitrogen source, and a cobalt precursor. The catalysts are then characterized using various methods to comprehensively study their properties coupled with ORR kinetics and stability. The CoO/NC2 catalyst shows higher catalytic activity towards ORR than the other in‐house prepared catalysts. It is comparable to commercial Pt/C and has very high stability for 80 h in an alkaline medium. Systematic analyses clarify that the superior electrocatalytic performance of CoO/NC2 stems mainly from its enhanced electron density and pathway by heteroatom doping and its modified carbon nature during spray pyrolysis.

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Section: Resultssupporting

confidence: 90%

“…The physical properties of the samples prepared in this study are listed in Table . The spray pyrolysis system, as shown in Figure S1, was described in our previous report . The precursor droplets produced by the nebulizer were placed in the reactor and maintained at 600 °C with a flow of N 2 .…”

Section: Methodsmentioning

confidence: 99%

Enhanced Oxygen Reduction Stability and Activity by Co and N (or O) Interaction in CoO on N‐Doped Carbon Prepared through Spray Pyrolysis

2018

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“…2,12,37 Relatively low intensity peaks were observed, in the case of Mn-NrGO sample, which is attributed to the small-sized crystallites of Mn 3 O 4 formed due to the graphitic substrate, 38 and the broad peak at around 27 of Mn-NrGO indicated the (002) graphitic plane of rGO. 25,39,40 Futhermore, the nitrogen dopant source (urea) did not change the crystal structure of Mn 3 O 4 . The high purity Mn-NrGO can be obtained through the pyrolysis at high temperature condition of 900 C and α-MnO 2 phase can be removed.…”

Section: Resultsmentioning

confidence: 93%

“…However, 3D crumpled graphene provides aggregation resistance even during electrochemical stability tests under harsh conditions. 23,25,26 Hence, several groups have reported manganese oxide-graphene composites with enhanced cycle performance and rate capability as anodes for the LIBs. For instance, Wang et al prepared a graphene/Mn 3 O 4 hybrid by a two-step hydrothermal process, with high reversible capacity of 700 mAh/g after 100 cycles at a current density of 100 mA/g.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical performance of Mn ₃ O ₄ nanorods by N‐doped reduced graphene oxide using ultrasonic spray pyrolysis for lithium storage

et al. 2020

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The crumpled N-doped reduced graphene oxide wrapped Mn 3 O 4 nanorods (Mn-NrGO) composite are synthesized via a combination of spray pyrolysis and a hydrothermal process for lithium ion batteries. The Mn 3 O 4 nanorods are uniformly dispersed in the conductive matrix of crumpled N-doped reduced graphene oxide, forming a uniform wrapped composite and stopping them from restacking, which synergistically enhanced the Li + ion conductivity. The well-defined Mn 3 O 4 nanorods, strong interaction between Mn 3 O 4 and NrGO, and highly graphitic properties of Mn-NrGO result in superior reversible capacity, long cycle life, and superior rate performance of approximately 1500 mAh/g at 0.1 C after 100 cycles and >660S mAh/g at 1.0 C after 500 cycles. K E Y W O R D S anode, lithium ion batteries, manganese oxide (Mn 3 O 4), nitrogen doped reduced graphene oxide (NrGO), spray pyrolysis

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“…Gurrola et al (2013) Sb-doped SnO 2 (ATO) ATO support showed enhanced stability & conductivity compared to carbon black Vulcan xC-72. Kim et al (2017) Crumpled rGO Heat-treated Pt-Ir/rGOs at 600°C showed increased ORR activity and nearly identical OER polarization trend compared to Pt/C. Kong et al 2015 SBA-15 template (s-IrO 2 ) s-IrO 2 catalyst revealed to have enhanced OER catalytic behavior and ORR efficiency rather than Pt/commercial IrO 2 .…”

Section: Electrocatalyst Supportmentioning

confidence: 99%

Recent Perspectives and Crucial Challenges on Unitized Regenerative Fuel Cell (URFC)

Hasran¹,

Pauzi²,

Basri³

et al. 2018

JKUKM

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Renewable sources of energy are becoming increasingly popular in recent years. The idea of using alternative energy that utilizes renewable sources is to slowly replace our dependence on fossil fuels. Conventional fossil fuels are not viable due to the fact that they are predominantly unsustainable over the long run. Furthermore, pollution will be reduced through the use of cleaner and more environmentally friendly renewable energy. Polymer electrolyte membrane fuel cell (PEMFC), which utilizes hydrogen as fuel, has a high potential as an alternative power generator. The unitized regenerative fuel cell (URFC) is a type of PEMFC that can perform both in charge mode (as a fuel cell) and discharge mode (as an electrolyzer). This review looks into the recent researches on the structure and different components of the URFC. In particular, emphasis is placed on bifunctional electrodes. Recent development in URFC research has produced a more stable bifunctional electrode with improved energy efficiency and overall stability and durability. Various works have been carried out to replace Pt as the electrocatalyst, including the use of graphene as a low cost non-metal graphene-based electrocatalyst. Electrocatalyst support also plays an important role in increasing conductivity while reducing the catalyst resistance to corrosion. The technological challenges and limitations of the URFC system are also discussed in this review.

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Crumpled rGO-supported Pt-Ir bifunctional catalyst prepared by spray pyrolysis for unitized regenerative fuel cells

Cited by 43 publications

References 56 publications

Enhanced Oxygen Reduction Stability and Activity by Co and N (or O) Interaction in CoO on N‐Doped Carbon Prepared through Spray Pyrolysis

Enhanced Oxygen Reduction Stability and Activity by Co and N (or O) Interaction in CoO on N‐Doped Carbon Prepared through Spray Pyrolysis

Electrochemical performance of Mn ₃ O ₄ nanorods by N‐doped reduced graphene oxide using ultrasonic spray pyrolysis for lithium storage

Recent Perspectives and Crucial Challenges on Unitized Regenerative Fuel Cell (URFC)

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Crumpled rGO-supported Pt-Ir bifunctional catalyst prepared by spray pyrolysis for unitized regenerative fuel cells

Cited by 43 publications

References 56 publications

Enhanced Oxygen Reduction Stability and Activity by Co and N (or O) Interaction in CoO on N‐Doped Carbon Prepared through Spray Pyrolysis

Enhanced Oxygen Reduction Stability and Activity by Co and N (or O) Interaction in CoO on N‐Doped Carbon Prepared through Spray Pyrolysis

Electrochemical performance of Mn 3 O 4 nanorods by N‐doped reduced graphene oxide using ultrasonic spray pyrolysis for lithium storage

Recent Perspectives and Crucial Challenges on Unitized Regenerative Fuel Cell (URFC)

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Product

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Electrochemical performance of Mn ₃ O ₄ nanorods by N‐doped reduced graphene oxide using ultrasonic spray pyrolysis for lithium storage