Platinum-Based Carbon Nanodots Nanocatalysts for Direct Alcohol Fuel Cells

Gwebu, Sandile Surprise; Nomngongo, Philiswa N.; Maxakato, Nobanathi Wendy

doi:10.5772/intechopen.82854

Cited by 2 publications

(2 citation statements)

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“…Carbon nanodots (CNDs), nanohorns (CNHs), and nanocoils (CNCs) have also been studied as catalyst supports. In the case of CNDs, apart from their facile synthesis and low cost of production, their small size (10 nm) provides a high surface area suitable for the dispersion of metal NPs while their high oxygen content (∼10%) is considered advantageous since there is no need for further functionalization prior to the deposition of the metal catalyst . Comparably, semiconducting carbon nanohorns (CNHs) that consist of horn-shaped aggregates of graphene with diameters of about 2–5 nm and lengths from 40 to 50 nm also demonstrate a high surface area that can reach up to 1025 m 2 /g .…”

Section: Electrocatalyst Supportsmentioning

confidence: 99%

“…In the case of CNDs, apart from their facile synthesis and low cost of production, their small size (10 nm) provides a high surface area suitable for the dispersion of metal NPs while their high oxygen content (∼10%) is considered advantageous since there is no need for further functionalization prior to the deposition of the metal catalyst. 600 Comparably, semiconducting carbon nanohorns (CNHs) that consist of horn-shaped aggregates of graphene with diameters of about 2−5 nm and lengths from 40 to 50 nm 601 also demonstrate a high surface area that can reach up to 1025 m 2 /g. 602 Finally, CNCs, a category of CNFs that have a helical shape, a low content of micropores, and a high electrical conductivity have been examined as supports for catalytic NPs in DMFCs and PEMFCs exhibiting promising performances.…”

Section: Carbon Catalysts Supportsmentioning

confidence: 99%

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Electrocatalysis in Alkaline Media and Alkaline Membrane-Based Energy Technologies

et al. 2022

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Hydrogen energy-based electrochemical energy conversion technologies offer the promise of enabling a transition of the global energy landscape from fossil fuels to renewable energy. Here, we present a comprehensive review of the fundamentals of electrocatalysis in alkaline media and applications in alkaline-based energy technologies, particularly alkaline fuel cells and water electrolyzers. Anion exchange (alkaline) membrane fuel cells (AEMFCs) enable the use of nonprecious electrocatalysts for the sluggish oxygen reduction reaction (ORR), relative to proton exchange membrane fuel cells (PEMFCs), which require Pt-based electrocatalysts. However, the hydrogen oxidation reaction (HOR) kinetics is significantly slower in alkaline media than in acidic media. Understanding these phenomena requires applying theoretical and experimental methods to unravel molecularlevel thermodynamics and kinetics of hydrogen and oxygen electrocatalysis and, particularly, the proton-coupled electron transfer (PCET) process that takes place in a proton-deficient alkaline media. Extensive electrochemical and spectroscopic studies, on single-crystal Pt and metal oxides, have contributed to the development of activity descriptors, as well as the identification of the nature of active sites, and the rate-determining steps of the HOR and ORR. Among these, the structure and reactivity of interfacial water serve as key potential and pH-dependent kinetic factors that are helping elucidate the origins of the HOR and ORR activity differences in acids and bases. Additionally, deliberately modulating and controlling catalyst−support interactions have provided valuable insights for enhancing catalyst accessibility and durability during operation. The design and synthesis of highly conductive and durable alkaline membranes/ionomers have enabled AEMFCs to reach initial performance metrics equal to or higher than those of PEMFCs. We emphasize the importance of using membrane electrode assemblies (MEAs) to integrate the often separately pursued/optimized electrocatalyst/support and membranes/ionomer components. Operando/in situ methods, at multiscales, and ab initio simulations provide a mechanistic understanding of electron, ion, and mass transport at catalyst/ionomer/membrane interfaces and the necessary guidance to achieve fuel cell operation in air over thousands of hours. We hope that this Review will serve as a roadmap for advancing the scientific understanding of the fundamental factors governing electrochemical energy conversion in alkaline media with the ultimate goal of achieving ultralow Pt or precious-metal-free highperformance and durable alkaline fuel cells and related technologies.

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Section: Electrocatalyst Supportsmentioning

confidence: 99%

Section: Carbon Catalysts Supportsmentioning

confidence: 99%