Small Reduced Graphene Oxides for Highly Efficient Oxygen Reduction Catalysts

Bak, Su-Jeong; Kim, Sun-I; Lim, Su-yeong; Kim, Taehyo; Kwon, Sun-Hong; Lee, Duck Hyun

doi:10.3390/ijms222212300

Cited by 7 publications

(11 citation statements)

References 36 publications

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“…In the polyol process, the liquid organic compound, a polyol, including 1,2-diols and ether glycols, acts both as a solvent of the solid precursor and as a reducing agent determining important process characteristics [ 42 , 43 ]: (1) the high boiling point allows synthesis at relatively high temperatures and ensures well-crystallized nanomaterials; (2) the reducing medium protects the as-prepared particles from contamination, as long as they remain in the medium; and (3) the high viscosity of the medium minimizes coalescence and favors a diffusion-controlled regime for particle growth, resulting in controlled structures and morphologies. Thus, the polyol process offers several advantages, including the easy control of nanomaterials, low cost, and verified scalability for industrial applications [ 42 , 44 ].…”

Section: Introductionmentioning

confidence: 99%

Polyol-Mediated Synthesis of V2O5–WO3/TiO2 Catalysts for Low-Temperature Selective Catalytic Reduction with Ammonia

et al. 2022

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We demonstrated highly efficient selective catalytic reduction catalysts by adopting the polyol process, and the prepared catalysts exhibited a high nitrogen oxide (NOX) removal efficiency of 96% at 250 °C. The V2O5 and WO3 catalyst nanoparticles prepared using the polyol process were smaller (~10 nm) than those prepared using the impregnation method (~20 nm), and the small catalyst size enabled an increase in surface area and catalytic acid sites. The NOX removal efficiencies at temperatures between 200 and 250 °C were enhanced by approximately 30% compared to those of the catalysts prepared using the conventional impregnation method. The NH3-temperature-programmed desorption and H2-temperature-programmed reduction results confirmed that the polyol process produced more surface acid sites at low temperatures and enhanced the redox ability. The in situ Fourier-transform infrared spectra further elucidated the fast absorption of NH3 and its reduction with NO and O2 on the prepared catalyst surfaces. This study provides an effective approach to synthesizing efficient low-temperature SCR catalysts and may contribute to further studies related to other catalytic systems.

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Section: Introductionmentioning

confidence: 99%

Polyol-Mediated Synthesis of V2O5–WO3/TiO2 Catalysts for Low-Temperature Selective Catalytic Reduction with Ammonia

et al. 2022

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“…Proton exchange membrane fuel cells (PEMFCs) are considered clean energy sources for both stationary systems and portable devices because of their low operating temperature, fast startup, high energy efficiency, and high power density [ 1 , 2 , 3 ]. Since most automotives operate for 5000–20,000 h, the long-term durability of PEMFCs is essential for their commercial use.…”

Section: Introductionmentioning

confidence: 99%

“…However, CB is thermodynamically unstable under the operating conditions of PEMFCs, and the carbon oxidation reaction (COR) is accelerated at elevated temperatures and potentials. The COR causes the detachment or agglomeration of Pt nanoparticles owing to the weakening of the interactions between the nanoparticles and the carbon support, resulting in a decrease in the Pt surface area [ 3 , 4 ].…”

Section: Introductionmentioning

confidence: 99%

“…CNTs exhibit numerous desirable properties, including a large specific surface area, excellent electrochemical durability, high electrical conductivity, and excellent mechanical strength. When CNTs are used as the support for ORR catalysts, the high crystallinity of the CNTs enhances the conductivity of the catalysts, while the high specific surface area and large number of mesopores in the CNTs result in the high dispersibility of the Pt nanoparticles [ 3 , 5 , 6 , 8 , 9 , 10 , 11 , 12 , 13 ]. Wang et al demonstrated that a CNT support can suppress the sintering of Pt nanoparticles.…”

Section: Introductionmentioning

confidence: 99%

“…We had recently reported highly efficient ORR catalysts composed of uniform Pt nanoparticles supported on small rGO (srGO). The performance and stability of these Pt/srGO catalysts were better than those of Pt/rGO and Pt/CB catalysts [ 3 ].…”

Section: Introductionmentioning

confidence: 99%

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Hybrid Carbon Supports Composed of Small Reduced Graphene Oxide and Carbon Nanotubes for Durable Oxygen Reduction Catalysts in Proton Exchange Membrane Fuel Cells

Bak

Son

Shin

et al. 2022

IJMS

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We demonstrated highly active and durable hybrid catalysts (HCs) composed of small reduced graphene oxide (srGO) and carbon nanotubes (CNTs) for use as oxygen reduction reaction (ORR) catalysts in proton exchange membrane fuel cells. Pt/srGO and Pt/CNTs were prepared by loading Pt nanoparticles onto srGO and CNTs using a polyol process, and HCs with different Pt/CNT and Pt/srGO ratios were prepared by mechanically mixing the two components. The prepared HCs consisted of Pt/CNTs well dispersed on Pt/srGO, with catalyst HC55, which was prepared using Pt/srGO and Pt/CNTs in a 5:5 ratio, exhibiting excellent oxygen reduction performance and high stability over 1000 cycles of the accelerated durability test (ADT). In particular, after 1000 cycles of the ADT, the normalized electrochemically active surface area of Pt/HC55 decreased by 11.9%, while those of Pt/srGO and Pt/C decreased by 21.2% and 57.6%, respectively. CNTs have strong corrosion resistance because there are fewer defect sites on the surface, and the addition of CNTs in rGO further improved the durability and the electrical conductivity of the catalyst. A detailed analysis of the structural and electrochemical properties of the synthesized catalysts suggested that the synergetic effects of the high specific surface area of srGO and the excellent electrical conductivity of CNTs were responsible for the enhanced efficiency and durability of the catalysts.

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Polyvinyl alcohol‐modified graphene oxide as a support for bimetallic Pt–Pd electrocatalysts to enhance the efficiency of formic acid oxidation

Saipanya

Themsirimongkon

et al. 2022

Polymers for Advanced Techs

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The aim of this research was to study the efficiency of polyvinyl alcohol (PVA)modified graphene oxide (GO) as a supporting material for catalysts that oxidize formic acid. The active metal catalysts (e.g., Pt and Pd) were electrodeposited on PVA/GO surfaces. The morphologies of the prepared catalysts were characterized by scanning electron microscopy and transmission electron microscopy, while their chemical compositions were identified by X-ray diffraction and X-ray photoelectron spectroscopy. The results show that compared with the other catalysts on GO, the prepared active PtPd alloy catalyst nanoparticles with 11.49-20.73 nm sizes were well dispersed on the PVA/GO surfaces. Electrochemical results indicate that the activities of the catalysts with PVA provided a higher current density than that of the catalysts without PVA. The bimetallic 3Pt3Pd/PVA/GO catalyst showed the greatest catalytic activity, stability, and CO oxidation when compared to those of other catalysts. The electronic, morphological, and structural properties promote the masscharge transfer through the interaction. These results indicate that the PVA-modified GO provides a suitable site for active bimetallic catalyst surfaces, resulting in excellent formic acid oxidation and high CO elimination. The 3Pt3Pd/PVA/GO electrocatalyst is promising for enhancing formic acid oxidation.

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Small Reduced Graphene Oxides for Highly Efficient Oxygen Reduction Catalysts

Cited by 7 publications

References 36 publications

Polyol-Mediated Synthesis of V2O5–WO3/TiO2 Catalysts for Low-Temperature Selective Catalytic Reduction with Ammonia

Polyol-Mediated Synthesis of V2O5–WO3/TiO2 Catalysts for Low-Temperature Selective Catalytic Reduction with Ammonia

Hybrid Carbon Supports Composed of Small Reduced Graphene Oxide and Carbon Nanotubes for Durable Oxygen Reduction Catalysts in Proton Exchange Membrane Fuel Cells

Polyvinyl alcohol‐modified graphene oxide as a support for bimetallic Pt–Pd electrocatalysts to enhance the efficiency of formic acid oxidation

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