Nickel nanocrystal/sulfur-doped carbon composites as efficient and stable electrocatalysts for urea oxidation reaction

Wu, Na; Zhang, Xue; Guo, Ruihong; Ma, Mingming; Zhang, Yujuan

doi:10.1016/j.jallcom.2022.163916

Cited by 19 publications

(6 citation statements)

References 56 publications

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“…The non-ultrasonicated NiFe-LDH (N-NiFe-LDH) electrocatalyst was synthesized by only being dipped in FeCl 3 solution without EG. The synthesis of H-NiFe-LDH can be found in the Supporting Information (Text S2), and the synthetic route for RuO 2 and Pt/C is presented in Text S3 …”

Section: Methodsmentioning

confidence: 99%

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Facile, Controllable, and Ultrathin NiFe-LDH In Situ Grown on a Ni Foam by Ultrasonic Self-Etching for Highly Efficient Urine Conversion

Zhao

Zhang

Xie

et al. 2023

Environ. Sci. Technol.

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As the primary source of nitrogen pollutants in domestic sewage, urine is also an alternative for H 2 production via electrochemical processes. However, it suffers from sluggish kinetics and noble-metal catalyst requirement. Here, we report a non-precious ultrathin NiFe-layered double hydroxide catalyst for the remarkable conversion of urea into N 2 and H 2 , which is in situ grown on a Ni foam via ultrasonic self-etching in Fe 3+ /ethylene glycol (EG). EG regulates the etching rate of Fe 3+ , resulting in an ultrathin nanosheet structure with the aid of ultrasonication. This structure dramatically promotes the dehydrogenation process via decreasing the nanolayer thickness from 120 to 3.4 nm and leads to a 4.8-fold increase in the generation of active sites. It exhibits record urea oxidation kinetics (390.8 mA•cm −2 at 1.5 V vs RHE) with excellent stability (120 h), which is 11.8 times better than that of commercial Pt/C catalyst (33.1 mA•cm −2 ). Tests with real urine at 20 mA cm −2 achieve 74% total nitrogen removal and 2853 μmol•h −1 of H 2 production. This study provides an attractive landscape for producing H 2 by consuming urine biowastes.

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Section: Methodsmentioning

confidence: 99%

“…The synthesis of H-NiFe-LDH can be found in the Supporting Information (Text S2), 45 and the synthetic route for RuO 2 and Pt/C is presented in Text S3. 46 2.2. Characterization.…”

Section: Synthesis Of the U-nife-ldh Electrocatalystmentioning

confidence: 99%

Facile, Controllable, and Ultrathin NiFe-LDH In Situ Grown on a Ni Foam by Ultrasonic Self-Etching for Highly Efficient Urine Conversion

Zhao

Zhang

Xie

et al. 2023

Environ. Sci. Technol.

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“…In our result we understand that there is a linear relationship between the curve of current density and the square root of the scan rate. Therefore, the transformation reaction from nickel(II) hydroxide (Ni(OH) 2 ) to nickel oxide hydroxide (NiOOH) is controlled by the diffusion process, 57 and consequently, the obtained current density is directly related to the diffusion of electroactive species from the solution to the electrode surface. This behaviour could indicate that the electrochemical process is entirely controlled by diffusion as has been suggested in the literature which may include (i) diffusion of species inside the oxide film or (ii) incorporation/expulsion of H 3 O + and/or OHand may be hydrated cations associated with solvent transfer.…”

Section: Methodsmentioning

confidence: 99%

Enhanced Methanol Oxidation in Alkaline Media on Electrodeposited Ni Electrodes by Morphological and Crystallographic Evolution

Nasirpouri

Foruzin

2023

J. Electrochem. Soc.

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This research aims at exploiting the electrocatalytic behaviour of nano-crystalline nickel electrodes electrodeposited by different techniques including direct current (DC), pulse current (PC), or pulse reversal current (PRC) for methanol electrooxidation in alkaline solutions. We understand that PC electrodeposition forms pyramidal shaped grains with a preferential Bragg diffraction peak of (111), whereas PRC produced refined spherical grain morphology with a strong (200) diffraction peak. However, DC electrodeposition exhibits an intermediate morphology and crystalline structure. Cyclic voltammetry (CV), and electrochemical impedance spectroscopy show that PRC electrodeposition develops Ni electrodes with better electrocatalytic activity for methanol electrooxidation than other two nickel electrodes. Based on the CV curve, the current density for Ni prepared by PRC electrodeposition methods is about 75.26 mA.cm-2, which is higher than those of DC and PC methods. This higher activity of PRC electrodeposited nickel is attributed to the low charge transfer resistance confirmed by Nyquist plots. We attributed this behavior to the (200)-oriented crystallographic texture, spherical grain morphology, and consequently the high electrochemical active surface area of this nickel electrode. This work reveals the importance of surface morphology and crystallography on the electrocatalytic behaviour of nickel electrodes for electrochemical energy devices.

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“…In addition, the high abundance of urea makes it a high potential candidate to replace hydrogen as fuel in fuel cells. − Urea can be found in large quantities in factory waste and from adult humans, who generally excrete 1.5 L of urine containing around 2–2.5% by weight of urea, equivalent to around 11 kg of urea per year. − However, one major limitation of the urea oxidation reaction (UOR) is slow reaction kinetics. Accordingly, it is necessary to develop a highly efficient UOR electrocatalyst to reduce the reaction limitations and increase the reaction rate. − …”

Section: Introductionmentioning

confidence: 99%

Crystallization of NiCo MOF-74 on a Porous NiO Film as an Anode for the Urea/H₂O₂ Fuel Cell

Putri

Chamberlain

Degirmenci

et al. 2023

ACS Appl. Energy Mater.

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NiCo-MOF-74 crystallized directly on the surface of porous NiO (p-NiO) film using a solvothermal method is proposed as an effective electrocatalyst for the anode in direct urea fuel cells. A nickel-to-cobalt ratio of 4:1 was found to show optimum catalytic activity toward urea oxidation with significant current enhancement in comparison to other electrodes, including Ni foil and p-NiO. At optimized conditions in an electrolyte solution of 3.0 M KOH and 1.0 M urea, a current density of around 110 mA cm −2 with a maximum power density of 4131 μW cm −2 can be produced. This is ascribed to the increase of the active surface area over conventional nickel-based anodes, providing an abundance of active sites for urea oxidation. Excellent stability and reproducibility over 15 h application in a direct urea fuel cell was obtained with cell voltage of ∼0.6 V. Powder X-ray diffraction shows the crystalline MOF film remains intact after chronoamperometry tests, and after fuel cell application, illustrating applicability in real devices.

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Nickel nanocrystal/sulfur-doped carbon composites as efficient and stable electrocatalysts for urea oxidation reaction

Cited by 19 publications

References 56 publications

Facile, Controllable, and Ultrathin NiFe-LDH In Situ Grown on a Ni Foam by Ultrasonic Self-Etching for Highly Efficient Urine Conversion

Facile, Controllable, and Ultrathin NiFe-LDH In Situ Grown on a Ni Foam by Ultrasonic Self-Etching for Highly Efficient Urine Conversion

Enhanced Methanol Oxidation in Alkaline Media on Electrodeposited Ni Electrodes by Morphological and Crystallographic Evolution

Crystallization of NiCo MOF-74 on a Porous NiO Film as an Anode for the Urea/H₂O₂ Fuel Cell

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Nickel nanocrystal/sulfur-doped carbon composites as efficient and stable electrocatalysts for urea oxidation reaction

Cited by 19 publications

References 56 publications

Facile, Controllable, and Ultrathin NiFe-LDH In Situ Grown on a Ni Foam by Ultrasonic Self-Etching for Highly Efficient Urine Conversion

Facile, Controllable, and Ultrathin NiFe-LDH In Situ Grown on a Ni Foam by Ultrasonic Self-Etching for Highly Efficient Urine Conversion

Enhanced Methanol Oxidation in Alkaline Media on Electrodeposited Ni Electrodes by Morphological and Crystallographic Evolution

Crystallization of NiCo MOF-74 on a Porous NiO Film as an Anode for the Urea/H2O2 Fuel Cell

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Crystallization of NiCo MOF-74 on a Porous NiO Film as an Anode for the Urea/H₂O₂ Fuel Cell