Self-supported Ni(OH)2/MnO2 on CFP as a flexible anode towards electrocatalytic urea conversion: The role of composition on activity, redox states and reaction dynamics

Meng, Jianfang; Chernev, Petko; Mohammadi, Mohammad Reza; Klingan, Katharina; Loos, Stefan; Pasquini, Chiara; Kubella, Paul; Jiang, Shan; Yang, Xianjin; Cui, Zhenduo; Zhu, Shengli; Li, Zhaoyang; Liang, Yanqin; Dau, Holger

doi:10.1016/j.electacta.2019.06.013

Cited by 37 publications

(15 citation statements)

References 62 publications

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“…However, these methods generally suffer from high costs, harsh working conditions, or excessive energy consumption, which greatly impede their broader application. 11–13…”

Section: Introductionmentioning

confidence: 99%

Strategies for designing more efficient electrocatalysts towards the urea oxidation reaction

et al. 2022

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“…However, these methods generally suffer from high costs, harsh working conditions, or excessive energy consumption, which greatly impede their broader application. 11–13…”

Section: Introductionmentioning

confidence: 99%

Strategies for designing more efficient electrocatalysts towards the urea oxidation reaction

et al. 2022

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“…34 The Co 2+ :Co 3+ mass ratios (Figure S5a regeneration on the electrode surface. 44,55 For the sake of verifying the correlation between the oxidation equivalence 56 The UOR kinetic performance determined by the electron transfer process was evaluated by the Tafel slope in 1 M KOH and 0.33 M urea electrolyte (Figure 5e). The catalysts performed a linear E-log(i) behavior between 1.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Spin State Tuning of the Octahedral Sites in Ni–Co-Based Spinel toward Highly Efficient Urea Oxidation Reaction

et al. 2021

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Nickel−cobalt spinel oxide is an efficient electrocatalyst for urea oxidation reaction (UOR) due to its low cost and high activity. The e g orbital occupancy of transition metal ions in spinel oxides can determine the oxygen evolution reaction activity. However, the e g filling, the catalyzing active sites, and the related UOR mechanisms in spinel catalysts are still unknown. Here, from the perspective of electronic structure and metal redox capability, we explored the composition dependence of urchin-like Ni x Co 3−x O 4 (x = 0, 0.75, 0.86, 1, and 1.20) spinel in UOR to investigate the role of octahedral nickel atoms in the spinel structure. The results indicated that the UOR activity could be promoted by embedding more Ni ions into the octahedral sites, allowing the accumulation of a large number of nickel redox equivalents and an increase in the level of the low-spin state of Ni 3+ . Furthermore, a near-unity occupancy of the e g orbital of Ni ions could enhance the intrinsic UOR activity of spinel catalysts. Urea oxidation proceeds through the electrochemical oxidation mechanism and direct urea electro-oxidation reaction pathway, where NiOOH species act as active sites in catalyzing the process. This work offers a guideline for designing and synthesizing non-precious metal-coupled Ni-based catalysts with appropriate redox properties for urea oxidation applications.

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“…[21,22] However, the mixture of nickel hydroxides and manganese oxide was reported to have high urea conversion efficiency. [23] Supporting materials is one of the main factors that significantly influence the catalyst's stability, electrochemical behavior, and catalytic activity. High surface area and high porosity of the support materials promote the better distribution of catalyst and reduce its amount, which helps decrease cost and enhance stability.…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, Ni/Mn binary catalysts were reported for urea electrooxidation like Ni−Mn@carbon nanofiber and Ni−Mn@activated carbon that achieved high anodic current density exceeding 130 mA.cm −2 [21,22] . However, the mixture of nickel hydroxides and manganese oxide was reported to have high urea conversion efficiency [23] …”

Section: Introductionmentioning

confidence: 99%

NiO‐MnOx/Polyaniline/Graphite Electrodes for Urea Electrocatalysis: Synergetic Effect between Polymorphs of MnOx and NiO.

et al. 2022

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In this work, we are enhancing the catalytic activity of the urea electrooxidation (UEO) process by using the composite of polyaniline (Pani), nickel oxide (NiO), and polymorphs of manganese oxide (MnOx) based on a graphite electrode. The hydro‐gel method was used to prepare catalyst suspension with different ratios from NiO and MnOx. The chemical structures and surface morphology were characterized by employing the IR, XRD, and SEM/EDEX techniques. The catalytic activity of four modified electrocatalysts G/Pani/NiMn1, G/Pani/NiMn2, G/Pani/NiMn3, G/Pani/NiMn4 was investigated using cyclic voltammetry, chronoamperometry, and electrochemical impedance. The kinetic parameters such as diffusion coefficient, Tafel slope, charge transfer coefficient, and surface coverage were calculated to choose the best electrocatalysts toward UEO in alkaline solution. The anodic current of new electrodes achieved about 16 mA.cm−2 at potential of 550 mV (vs. Ag/AgCl). Density functional theory studies (DFT) have been carried out to assess the adsorption energy between polyaniline (Pani) and the metal oxides.

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Self-supported Ni(OH)2/MnO2 on CFP as a flexible anode towards electrocatalytic urea conversion: The role of composition on activity, redox states and reaction dynamics

Cited by 37 publications

References 62 publications

Strategies for designing more efficient electrocatalysts towards the urea oxidation reaction

Strategies for designing more efficient electrocatalysts towards the urea oxidation reaction

Spin State Tuning of the Octahedral Sites in Ni–Co-Based Spinel toward Highly Efficient Urea Oxidation Reaction

NiO‐MnOx/Polyaniline/Graphite Electrodes for Urea Electrocatalysis: Synergetic Effect between Polymorphs of MnOx and NiO.

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