Solid solution palladium-nickel bimetallic anode catalysts by co-sputtering for direct urea fuel cells (DUFC)

Yoon, Jaesik; Lee, Doohee; Lee, Yu Na; Yoon, Young Soo; Kim, Dong-Joo

doi:10.1016/j.jpowsour.2019.05.059

Cited by 46 publications

(32 citation statements)

References 39 publications

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“…The UOR efficiency is significantly dependent on the selection of catalysts. Currently, platinum-and rutheniumbased materials are the catalysts of choice for UOR in both neutral and base media, [10][11][12][13] but high costs, limited availability, and natural scarcity have hindered their widespread applications. Thus, significant efforts have been devoted to the development of high-efficiency UOR catalysts based on earth-abundant, costeffective materials.…”

Section: Introductionmentioning

confidence: 99%

An Unveiled Electrocatalysis Essence of NiCo Hydroxides through in Situ Raman Spectroscopy for Urea Oxidation

Zhang

et al. 2022

Energy Tech

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The electrochemical urea oxidation reaction (UOR) is the performance‐limiting half reaction of urea electrolysis for producing renewable hydrogen energy. Nevertheless, the essence of electrode function mechanism of catalysts remains unclear. Therefore, design and optimization of catalysts are restricted. Herein, an in situ Raman spectroscopy method is employed to directly measure the electrode properties of the NiCo double hydroxides (NiCo DHs) under working conditions. Given definitely evidence, the evolution process of in situ Raman spectra shows that the Ni element is converted to NiOOH under UOR potentials, while the Co dopant is converted to CoOOH and further to higher‐valence CoO2 species. Obviously, the catalytically active phase toward UOR is really a complex NiOOH–CoOOH–CoO2 phase. Accurately matched spectral wavenumbers and electrochemical measurements of the catalytic electrodes explicitly reveal that the addition of Co assuredly reduces the onset potential for electroactive NiOOH formation. The Raman results also indicate effects of the NiO bond elongation and increased disorder caused by Co doping. Herein, an important understanding and new mechanistic perspectives for the electrode reaction process of UOR with NiCo binary catalysts are provided.

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Section: Introductionmentioning

confidence: 99%

An Unveiled Electrocatalysis Essence of NiCo Hydroxides through in Situ Raman Spectroscopy for Urea Oxidation

Zhang

et al. 2022

Energy Tech

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“…The DUFC power density exhibited by the Ni–Pd (1.12 mW cm −2 ) was higher compared with those of Ni–Pt/C (≈0.65 mW cm −2 ) and Ni–Ag/C (≈0.29 mW cm −2 ) against 0.33 m urea/1 m KOH at room temperature, ascribed to the work function of Ni–Pd and the catalyst regeneration mechanism at the anode. [ 69 ]…”

Section: Recent Developments In Dufc Uor Catalystsmentioning

confidence: 99%

Direct Urea Fuel Cells: Recent Progress and Critical Challenges of Urea Oxidation Electrocatalysis

kumar

Farithkhan

Manthiram

2020

Adv Energy and Sustain Res

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Direct urea fuel cells (DUFCs) are proven as environmentally benign energy generation devices and hold superior potential to meet the booming energy demand with the use of waste‐water containing urea/urine as a fuel. Despite the high theoretical gravimetric energy density, DUFC's experimentally projected value is substantially lower, due to the sluggish electrokinetics of urea oxidation reaction (UOR). The key to realizing high performance, durable DUFCs is reliant upon the advancement of electrode materials encompassing electrochemically active and stable UOR nanocatalysts. Furthermore, an in‐depth electromechanistic understanding of UOR and the use of human urine as a fuel are of great importance to the scale‐up objectives of DUFCs. Herein, the comprehensive portrayal of these salient aspects along with the scientific breakthroughs of UOR catalysts applicable to DUFCs is essential for the practical augmentation of DUFCs. Accordingly, a comprehensive portrayal of background overview, operating principles, UOR mechanism, and recent advances made on UOR catalysts, with the fundamental aspects of electrochemistry and fuel cells, as well as the critical challenges of existing UOR catalysts is presented. Also, the research and scale‐up challenges of UOR catalysts‐equipped DUFCs are outlined with futuristic perspectives to enhance their viability in sustainable energy generation.

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“…For instance, the NiÀ Co catalyst was frequently adopted in literature, producing high power outputs ranging from 1.4 to 21.7 mW cm À 2 . [9,10,[20][21][22][23][24][25] Alternatively, NiÀ Cu, [26] NiÀ Pd, [27,28] NiÀ Cr, [29] and Ni-Fe [30][31][32] catalysts have also been explored. Among these Ni-based bimetallic catalysts, a layered double hydroxide (LDH) structure is especially advantageous owning to its unique properties such as tunable metal species and molar ratios.…”

Section: Introductionmentioning

confidence: 99%

Ni‐Fe Layered Double Hydroxide Nanosheets Supported on Exfoliated Graphite for Efficient Urea Oxidation in Direct Urea Fuel Cells

et al. 2022

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Urea-rich wastewater can cause serious eutrophication problem to the water environment. On the other hand, urea is a potential fuel with high energy density, which can be effectively utilized by direct urea fuel cell. In this work, exfoliated graphite (EG) with high surface area and electrical conductivity was obtained by microwave irradiation, which was used to support the NiÀ Fe layered double hydroxide (LDH), leading to a highly efficient and low-cost urea oxidation catalyst. Compared with commercial RuO 2 , the as-prepared NiÀ Fe LDH/EG exhibited a lower onset potential of 1.25 V vs. reversible hydrogen electrode as well as a lower Tafel slope of 44 mV dec À 1 . The catalyst durability was also proved to be excellent. The optimized Ni/Fe molar ratio was confirmed to be 3 : 1, while the most suitable catalyst/EG ratio was 3 : 50. When applied in a dual-electrolyte direct urea fuel cell, the peak power density reached 12 mW cm À 2 , and the long-term discharge was also stable with negligible voltage loss at 10 mA cm À 2 for 3 h. Such a low-cost and efficient urea oxidation catalyst can be widely utilized in future direct urea fuel cells, which achieve wastewater treatment and renewable electricity generation at the same time.

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Solid solution palladium-nickel bimetallic anode catalysts by co-sputtering for direct urea fuel cells (DUFC)

Cited by 46 publications

References 39 publications

An Unveiled Electrocatalysis Essence of NiCo Hydroxides through in Situ Raman Spectroscopy for Urea Oxidation

An Unveiled Electrocatalysis Essence of NiCo Hydroxides through in Situ Raman Spectroscopy for Urea Oxidation

Direct Urea Fuel Cells: Recent Progress and Critical Challenges of Urea Oxidation Electrocatalysis

Ni‐Fe Layered Double Hydroxide Nanosheets Supported on Exfoliated Graphite for Efficient Urea Oxidation in Direct Urea Fuel Cells

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