Hybrid Porous Catalysts Derived from Metal–Organic Framework for Oxygen Reduction Reaction in an Anion Exchange Membrane Fuel Cell

Wang, Kai-Chin; Huang, Hsin‐Chih; Chang, Shinn‐Jen; Wu, Chenghao; Yamanaka, Ichiro; Lee, Jyh‐Fu; Wang, Chenhao

doi:10.1021/acssuschemeng.8b05993

Cited by 17 publications

(6 citation statements)

References 83 publications

(117 reference statements)

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“…The single cell performance of the prepared AEMs was measured at 60 °C in comparison with the Fumion-FAA-3 ionomer membrane (FAA-3-IM), and the results are shown in Figure a. The open circuit voltage (OCV) of all AEMs was greater than 0.96 V, indicating weak fuel gas permeability. − The power density of PYR-PAE-PhPh and PYR-PAE-BPHF was 109 mW cm –2 and 89 mW cm –2 , respectively. Meanwhile, the peak power density of FAA-3-IM (30 mW cm –2 ) was lower than that of the as-synthesized AEMs.…”

Section: Resultsmentioning

confidence: 99%

Study on the Chemical Stabilities of Poly(arylene ether) Random Copolymers for Alkaline Fuel Cells: Effect of Main Chain Structures with Different Monomer Units

Chu

Lee

Kim

et al. 2019

ACS Sustainable Chem. Eng.

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We developed a series of heterocyclic quaternary ammonium-type poly(arylene ether) (PAE) random copolymers with moieties of sulfone, ketone, hexafluoroisopropyl, isopropyl, phenolphthalein, or phenylene to identify differences in the physicochemical properties of the AEM due to polymer backbone structure containing electron-withdrawing groups (EWGs) or electron-donating groups (EDGs). The 1-methyl pyrrolidine (PYR)-PAE membranes containing EDGs exhibited higher hydroxide conductivity compared with PYR-PAE membranes with EWGs due to more distinctly separated ion transport sites, which was confirmed through AFM phase images. The ionic conductivity of all prepared membranes was greater than 89% after an alkaline stability test for 700 h in 2 M KOH at 70 °C, PYR-PAE membranes with EDGs higher than that of EWGs revealed stronger alkaline stability. In particular, the PYR-PAE-PhPh membrane retained the highest alkaline stability of 96.9% due to the steric hindrance effect. In fuel cell operation, the PYR-PAE-PhPh membrane representing EDGs showed a higher power density (109 mW cm −2 ) than that of the PYR-PAE-BPHF membrane (89 mW cm −2 ) and commercial AEM (Fumion-FAA-3, 30 mW cm −2 ). On the basis of these results, we suggest that structural design of the backbone is a critical strategy to develop an AEM with remarkable electrochemical properties and alkaline stability for alkaline fuel cell applications.

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Section: Resultsmentioning

confidence: 99%

Study on the Chemical Stabilities of Poly(arylene ether) Random Copolymers for Alkaline Fuel Cells: Effect of Main Chain Structures with Different Monomer Units

Chu

Lee

Kim

et al. 2019

ACS Sustainable Chem. Eng.

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“…Typically, the best performing mass loading of M–N–C catalysts in membrane electrode assemblies (MEAs) are generally range from 2 to 3 mg cm −2 . [ 49–51 ] However, the performance of our Co 1 /CNH 700 catalyst continues to with the loading amount of the catalyst, and the loading amount for its best performance is 6.0 mg cm −2 . It is believed that the 3D radial shape and porous nature of Co 1 /CNH 700 effectively facilitates the mass transfer of reactants and products, leading to the high utilization of active sites even in thick catalyst layers (Figure S19, Supporting Information).…”

Section: Resultsmentioning

confidence: 98%

Flash Bottom‐Up Arc Synthesis of Nanocarbons as a Universal Route for Fabricating Single‐Atom Electrocatalysts

et al. 2021

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Atomically dispersed metal atoms on supporting materials inherit the merits of both heterogeneous and homogeneous catalysts, such as the easy separation and high durability of a heterogeneous phase and the well-structured catalytic active sites and tunable activity of a homogeneous phase. [6][7][8] The isolated metals in SACs are located on neighboring surface atoms (metal oxide, metal nitride, and carbon atoms) or coordinated with heteroatoms, such as nitrogen, sulfur, and phosphorus. [7,[9][10][11] The metal centers and their surrounding atoms can be thought of as molecular catalytic sites that proceed down a highly selective reaction pathway. [12][13][14][15][16] For a decade, a variety of synthesis strategies have been developed to realize highly active SACs. [7,[17][18][19] One of the most widely applied methods is the defect engineering strategy. [1,[20][21][22] Preformed defects on supporting materials can alter the surrounding electronic state and have been used as effective "traps" to capture metal precursors and anchor metal atoms during post-treatment. [8,23] Another popular synthetic method is the spatial confinement strategy. Despite considerable development in the field of single-atom catalysts (SACs)on carbon-based materials, the reported strategies for synthesizing SACs generally rely on top-down approaches, which hinder achieving both simple and universal synthesis routes that are simultaneously applicable to various metals and nanocarbons. Here, a universal strategy for fabricating nanocarbon based-SACs using a flash bottom-up arc discharge method to mitigate these issues is reported. The ionization of elements and their recombination process during arc discharge allows the simultaneous incorporation of single metal atoms (Mn, Fe, Co, Ni, and Pt) into the crystalline carbon lattice during the formation of carbon nanohorns (CNHs) and N-doped arc graphene. The coordination environment around the Co atoms of Co 1 /CNH can be modulated by a mild post-treatment with NH 3 . As a result, Co 1 /CNH exhibits good oxygen reduction reaction activity, showing a 1.92 times higher kinetic current density value than the commercial Pt/C catalyst in alkaline media. In a single cell experiment, Co 1 /CNH exhibits the highest maximum power density of 472 mW cm −2 compared to previously reported nonprecious metal-based SACs.

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“…Furthermore, interfacing TMOs with metallic and conductive porous (nano)carbon phases is also advantageous for the anodic HOR, especially considering the sluggish HOR kinetics in alkaline medium. Accordingly, multicomponent systems are highly in demand for AEMFCs, which benefit from PGM-free electrocatalyst nanomaterials with promising stabilities under alkaline conditions. , Because ideal alkaline HOR catalysts should have both optimal hydroxyl- and hydrogen-binding energies, oxophilic surfaces developed by structural engineering can significantly boost HOR kinetics via increasing the number of active sites for the optimum adsorption of H* and OH* intermediate species. , Yang et al reported CeO 2 @Ni@C as a highly efficient HOR electrocatalyst for AEMFCs . They observed that the enhancement in the electron transfer between CeO 2 and Ni phases in the heterostructure led to thermoneutral adsorption free energies of H* with an optimal Δ G H * on the Ni surface, while the oxygen-vacancy-rich CeO 2 promoted the adsorption strength of OH* species.…”

Section: Nanomaterial-based Systems For Electrochemical Energy Conver...mentioning

confidence: 99%

Noble-Metal-Free Multicomponent Nanointegration for Sustainable Energy Conversion

et al. 2021

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Global energy and environmental crises are among the most pressing challenges facing humankind. To overcome these challenges, recent years have seen an upsurge of interest in the development and production of renewable chemical fuels as alternatives to the nonrenewable and high-polluting fossil fuels. Photocatalysis, photoelectrocatalysis, and electrocatalysis provide promising avenues for sustainable energy conversion. Single-and dual-component catalytic systems based on nanomaterials have been intensively studied for decades, but their intrinsic weaknesses hamper their practical applications. Multicomponent nanomaterial-based systems, consisting of three or more components with at least one component in the nanoscale, have recently emerged. The multiple components are integrated together to create synergistic effects and hence overcome the limitation for outperformance. Such higher-efficiency systems based on nanomaterials will potentially bring an additional benefit in balance-of-system costs if they exclude the use of noble metals, considering the expense and sustainability. It is therefore timely to review the research in this field, providing guidance in the development of noble-metal-free multicomponent nanointegration for sustainable energy conversion. In this work, we first recall the fundamentals of catalysis by nanomaterials, multicomponent nanointegration, and reactor configuration for water splitting, CO 2 reduction, and N 2 reduction. We then systematically review and discuss recent advances in multicomponent-based photocatalytic, photoelectrochemical, and electrochemical systems based on nanomaterials. On the basis of these systems, we further laterally evaluate different multicomponent integration strategies and highlight their impacts on catalytic activity, performance stability, and product selectivity. Finally, we provide conclusions and future prospects for multicomponent nanointegration. This work offers comprehensive insights into the development of cost-competitive multicomponent nanomaterial-based systems for sustainable energy-conversion technologies and assists researchers working toward addressing the global challenges in energy and the environment.

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Hybrid Porous Catalysts Derived from Metal–Organic Framework for Oxygen Reduction Reaction in an Anion Exchange Membrane Fuel Cell

Cited by 17 publications

References 83 publications

Study on the Chemical Stabilities of Poly(arylene ether) Random Copolymers for Alkaline Fuel Cells: Effect of Main Chain Structures with Different Monomer Units

Study on the Chemical Stabilities of Poly(arylene ether) Random Copolymers for Alkaline Fuel Cells: Effect of Main Chain Structures with Different Monomer Units

Flash Bottom‐Up Arc Synthesis of Nanocarbons as a Universal Route for Fabricating Single‐Atom Electrocatalysts

Noble-Metal-Free Multicomponent Nanointegration for Sustainable Energy Conversion

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