Co-doped Ni–Mo oxides: highly efficient and robust electrocatalysts for urea electrooxidation assisted hydrogen production

Liu, Xiangyun; Qin, Hehe; Wang, Genxiang; Li, Qiuju; Huang, Qingting; Wen, Zhenhai; Mao, Shun

doi:10.1039/d2ta04728d

Cited by 40 publications

(25 citation statements)

References 58 publications

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“…Alternatively, transition metal (TM)-based catalysts have been recently developed to replace PGM-based catalysts. In literature, transition metal hydroxides (TMH), ,, transition metal oxides (TMO), − transition metal phosphides (TMP), − and transition metal sulfides (TMS) − have been well researched. In contrast, TMPs have attracted great interest due to their lower costs, fast electron transport properties, and excellent proton trapping abilities. , …”

Section: Introductionmentioning

confidence: 99%

High-Density NiCu Bimetallic Phosphide Nanosheet Clusters Constructed by Cu-Induced Effect Boost Total Urea Hydrolysis for Hydrogen Production

Dong

Wang

et al. 2023

Inorg. Chem.

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The development of urea electrolysis technologies toward energysaving hydrogen production can alleviate the environmental issues caused by urea-rich wastewater. In the current practices, the development of highperformance electrocatalysts in urea electrolysis remains critical. In this work, the NiCu-P/NF catalyst is prepared by anchoring Ni/Cu bimetallic phosphide nanosheets onto Ni foam (NF). In the experiments, the micron-sized elemental Cu polyhedron is first anchored on the surface of the NF substrate to provide more space for the growth of bimetallic nanosheets. Meanwhile, the Cu element adjusted the electron distribution within the composite and formed Ni/P orbital vacancies, which in turn accelerated the kinetic process. As a result, the optimal NiCu-P/NF sample exhibits excellent catalytic activity and cycling stability in a hybrid electrolysis system for the urea oxidation reaction (UOR) and hydrogen evolution reaction (HER). Further, the alkaline urea-containing electrolyzer is assembled with NiCu-P/NF as two electrodes reached a current density of 50 mA cm −2 with a low driving potential of 1.422 V, which outperforms the typical commercial noble metal electrolyzer (RuO 2 ||Pt/C). Those findings suggest the feasibility of the substrate regulation strategy to increase the growth density of active species in preparation of an efficient bifunctional electrocatalyst for cracking the urea-containing wastewater.

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Section: Introductionmentioning

confidence: 99%

High-Density NiCu Bimetallic Phosphide Nanosheet Clusters Constructed by Cu-Induced Effect Boost Total Urea Hydrolysis for Hydrogen Production

Dong

Wang

et al. 2023

Inorg. Chem.

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“…For the Mo 3d spectrum of MoO 2 , the chemical states of high-valent Mo species like Mo 4+ , Mo 5+ , and Mo 6+ can be fitted, which is consistent with the reports elsewhere. 29,34 While for the spectrum of the NiO/MoO 2 -1:1 catalyst, a new peak assigned to Mo 2+ was observed at the binding energy of 229.0 eV (Table S2). 29,35,36 The observed Mo 2+ can well interpret the high-valent Ni species formation in the Ni 2p spectrum, probably due to a partial redox between the high-valent Mo 4+ and low-valent Ni 2+ species.…”

Section: Resultsmentioning

confidence: 99%

High-Valent Ni Species Induced by Inactive MoO₂ for Efficient Urea Oxidation Reaction

Huang

Wang

et al. 2022

Inorg. Chem.

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The microenvironment tuning of Ni species, a promising non-precious catalyst, is significant in the energy and environmentally relevant urea electro-oxidation reaction (UOR). Herein, we found that the high-valent Ni species induced by the inactive MoO2 in mixed nanocrystals of NiO/MoO2 were effective for urea oxidation. The redox interaction of MoO2 and NiO revealed by the spectroscopic analysis well supported the formation of high-valent Ni species and the changes in the surface chemical state. High catalytic activity and stability for urea oxidation were observed by a series of electrochemical measures compared to the counterpart catalysts of MoO2 and NiO. The optimal NiO/MoO2 hybrid catalyst showed a UOR activity of 73.1 mA cm–2 at 1.50 V, which was about 12-fold that of the NiO catalyst. In addition, largely improved catalytic kinetics and catalytic stability for UOR were also demonstrated. Because of the inactive activity of MoO2 and the low performance of NiO, the largely improved preference can be affirmatively attributed to the efficient catalytic synergism of NiO/MoO2 in the mixed nanocrystals. The current finding clarifies the catalytic promotion effect of the inactive Mo species on Ni-based catalysts for urea oxidation, which would be instructive for Ni/Mo-relevant catalyst development.

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“…Generally, hydrazine, urea, , and sodium borohydride are reported as sacrificial agents for hydrogen production. Among them, urea oxidation is gaining more attention nowadays to produce hydrogen because of several advantages . Generally, organic urea wastewater is directly discharged without treatment, causing serious pollution to the environment.…”

Section: Introductionmentioning

confidence: 99%

“…Among them, urea oxidation is gaining more attention nowadays to produce hydrogen because of several advantages. 23 Generally, organic urea wastewater is directly discharged without treatment, causing serious pollution to the environment. Also, urea can spontaneously decompose into a harmful gas, ammonia.…”

Section: ■ Introductionmentioning

confidence: 99%

Electrocatalytic Oxidation of Urea and Ethanol on Two-Dimensional Amorphous Nickel Oxide Encapsulated on N-Doped Carbon Nanosheets

Shekhawat

Samanta

Panigrahy

et al. 2023

ACS Appl. Energy Mater.

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Hydrogen production from water electrolysis is of great interest for attaining sustainable clean energy storage and conversion, but the required working voltage (>1.23 V) in water splitting limits its applications in industrial expansion. Therefore, replacing the oxygen evolution reaction (OER) with a more favorable anodic oxidation reaction, which can provide more valuable products and less working voltage, will be of great significance for the upcoming expansion of hydrogen production in industrial applications. In this report, a two-dimensional (2D) amorphous sheet-like nickel oxide encapsulated on the nitrogendoped carbon (NiO x /CN x ) composite was synthesized for the urea oxidation reaction (UOR) and ethanol oxidation reaction (EOR). Remarkably, the catalyst shows 1.647, 1.378, and 1.354 V vs. reversible hydrogen electrode (RHE) potential at 10 mA/cm 2 current density for OER, UOR, and EOR, respectively, with good stability. The overall water, urea, and ethanol electrolyses of NiO x /CN x were carried out by coupling with commercial Pt/C as a cathode which shows only 1.626, 1.43, and 1.414 V cell potential at 20 mA/cm 2 current density. The catalyst also shows excellent chronopotentiometric and dynamic stability toward all the electrolyses. The high catalytic activity of NiO x /CN x may be attributed to the synergistic interaction between the support and materials, amorphous structure, 2D sheet-like morphology, porous structure, and high electrochemical surface area. This finding shows that NiO x /CN x nanosheets can replace noble metal-based catalysts for efficient anodic oxidation reactions.

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Co-doped Ni–Mo oxides: highly efficient and robust electrocatalysts for urea electrooxidation assisted hydrogen production

Abstract: Electrolysis systems constructed by anodic urea oxidation reaction (UOR) and cathodic hydrogen evolution reaction (HER) have received considerable attention in sustainable energy and waste utilization.

Cited by 40 publications

References 58 publications

High-Density NiCu Bimetallic Phosphide Nanosheet Clusters Constructed by Cu-Induced Effect Boost Total Urea Hydrolysis for Hydrogen Production

High-Density NiCu Bimetallic Phosphide Nanosheet Clusters Constructed by Cu-Induced Effect Boost Total Urea Hydrolysis for Hydrogen Production

High-Valent Ni Species Induced by Inactive MoO₂ for Efficient Urea Oxidation Reaction

Electrocatalytic Oxidation of Urea and Ethanol on Two-Dimensional Amorphous Nickel Oxide Encapsulated on N-Doped Carbon Nanosheets

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Co-doped Ni–Mo oxides: highly efficient and robust electrocatalysts for urea electrooxidation assisted hydrogen production

Abstract: Electrolysis systems constructed by anodic urea oxidation reaction (UOR) and cathodic hydrogen evolution reaction (HER) have received considerable attention in sustainable energy and waste utilization.

Cited by 40 publications

References 58 publications

High-Density NiCu Bimetallic Phosphide Nanosheet Clusters Constructed by Cu-Induced Effect Boost Total Urea Hydrolysis for Hydrogen Production

High-Density NiCu Bimetallic Phosphide Nanosheet Clusters Constructed by Cu-Induced Effect Boost Total Urea Hydrolysis for Hydrogen Production

High-Valent Ni Species Induced by Inactive MoO2 for Efficient Urea Oxidation Reaction

Electrocatalytic Oxidation of Urea and Ethanol on Two-Dimensional Amorphous Nickel Oxide Encapsulated on N-Doped Carbon Nanosheets

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High-Valent Ni Species Induced by Inactive MoO₂ for Efficient Urea Oxidation Reaction