Enhanced performance and electrocatalytic kinetics of Ni-Mo/graphene nanocatalysts towards alkaline urea oxidation reaction

Shi, Wei; Ding, Rui; Li, Xudong; Xu, Qi; Liu, Enhui

doi:10.1016/j.electacta.2017.05.002

Cited by 120 publications

(60 citation statements)

References 26 publications

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“…As seen in Figure S4, the CuCo 2 O 4 electrode showed almost no change in potential during CV measurements at various scan rates, indicating superior rate capability for the UOR process. Tests performed by Shi et al demonstrated an increase in the anodic current density for the Ni/Mo/graphene nanocatalysts after addition of urea in the system [26]. This increase was also found by Barakat et al in the urea oxidation test for Ni and Mn nanoparticle-decorated carbon nanofibers [27].…”

Section: Electrocatalytic Activitiessupporting

confidence: 56%

Nanosheets of CuCo2O4 As a High-Performance Electrocatalyst in Urea Oxidation

Zequine

Wang

et al. 2019

Applied Sciences

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The urea oxidation reaction (UOR) is a possible solution to solve the world’s energy crisis. Fuel cells have been used in the UOR to generate hydrogen with a lower potential compared to water splitting, decreasing the costs of energy production. Urea is abundantly present in agricultural waste and in industrial and human wastewater. Besides generating hydrogen, this reaction provides a pathway to eliminate urea, which is a hazard in the environment and to people’s health. In this study, nanosheets of CuCo2O4 grown on nickel foam were synthesized as an electrocatalyst for urea oxidation to generate hydrogen as a green fuel. The synthesized electrocatalyst was characterized using X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The electroactivity of CuCo2O4 towards the oxidation of urea in alkaline solution was evaluated using electrochemical measurements. Nanosheets of CuCo2O4 grown on nickel foam required the potential of 1.36 V in 1 M KOH with 0.33 M urea to deliver a current density of 10 mA/cm2. The CuCo2O4 electrode was electrochemically stable for over 15 h of continuous measurements. The high catalytic activities for the hydrogen evolution reaction make the CuCo2O4 electrode a bifunctional catalyst and a promising electroactive material for hydrogen production. The two-electrode electrolyzer demanded a potential of 1.45 V, which was 260 mV less than that for the urea-free counterpart. Our study suggests that the CuCo2O4 electrode can be a promising material as an efficient UOR catalyst for fuel cells to generate hydrogen at a low cost.

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Section: Electrocatalytic Activitiessupporting

confidence: 56%

Nanosheets of CuCo2O4 As a High-Performance Electrocatalyst in Urea Oxidation

Zequine

Wang

et al. 2019

Applied Sciences

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“…Figure D reveals the Tafel slopes of UOR on Ni−Co−Se and Ni−Co−Se/CNT in the kinetic domain from 0.2 V to 0.28 V. The corresponding slopes were measured to be 87.2 mV/dec and 61.3 mV/dec, respectively. Such Tafel slope of CNT/Ni−Co−Se catalyst is lower than those of Ni 8 Mo 1 /G (110 mV/dec), MnO 2 nanocrystals (75 mV/dec), NiCo LDH‐NO 3 (91 mV/dec), NiO/MWCNTs (85.35 mV/dec), and NiO/Gr (90.87 mV/dec) …”

Section: Resultsmentioning

confidence: 84%

Heterostructured Nickel‐Cobalt Selenide Immobilized onto Porous Carbon Frameworks as an Advanced Anode Material for Urea Electrocatalysis

et al. 2019

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Transition-metal selenides based materials have recently aroused an increasing consideration in the field of energy reservation and conversion owing to their good electrochemical performance and low synthetic cost. Herein, multi-walled carbon nanotubes supported binary nickel cobalt selenide composite (NiÀ CoÀ Se/CNT) was prepared by a one-pot-hydrothermal method using hydrazine ions that enables the selenium to diffuse and react with the Ni-and Co-cations to form NiÀ CoÀ Se with a stable nanostructure onto the outer walls of the CNT platforms due to the coordination interaction between the metallic cations and surface oxygen-containing group of the conductive scaffolds. The electrochemical performances for urea oxidation reaction (UOR) are accessed in an alkaline medium by cyclic voltammetry (CV), chronopotentiometry (CA), and electrochemical impedancespectroscopy (EIS) tests. The asprepared NiÀ CoÀ Se/CNT hybrid presents an excellent electrocatalytic activity in terms of current density and onset potential due to synergistic effects of tubular CNT scaffolds, additional Co active sites, and electrochemically active NiOOH layer. The CNTs support markedly enhanced the electrocatalytic properties by providing a rapid mass transport for UOR because of their porous network architectures with a robust adhesion to the NiÀ CoÀ Se nanocrystals. Thus, the synthetic methodology synthetic methodology adopted here is entirely effective for constructing various metal selenide compounds in future.

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“…Moreover, the kinetics of UOR at the as‐obtained catalysts were studied by the Tafel plots (Figure S8, Supporting Information). It can be seen that the Tafel slope of the C@Ni 2 P NRs‐peapod catalyst was estimated to be 74.28 mV dec −1 , which is much smaller than that of C@Ni 2 P NPs (128.90 mV dec −1 ) and marginally less than those reported for Ni 8 Mo 1 (110 mV dec −1 ), NiCo layer double hydroxide with nitrate intercalant (NiCo LDH‐NO 3 ) (91 mV dec −1 ), Ni(OH) 2 ultrathin nanomeshes (NMs) (80 mV dec −1 ), Ni(OH) 2 ‐NPs (231 mV dec −1 ), NiO/multi‐walled carbon nanotubes (NiO/MWCNTs) (85.35 mV dec −1 ), NiO/Gr (90.87 mV dec −1 ), Ni 1 Mo 1 /Gr (160 mV dec −1 ), Ni 4 Mo 1 /Gr (139 mV dec −1 ), and Ni 3 Mo 2 /Gr (137 mV dec −1 ), implying faster reaction kinetics at C@Ni 2 P NRs‐peapod.…”

Section: Resultsmentioning

confidence: 77%

Shape‐Dependent Electrocatalytic Activity of Carbon Reinforced Ni₂P Hybrids Toward Urea Electrocatalysis

2019

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Recently, urea has aroused considerable interest as a potential hydrogen carrier to supply renewable energy; thus, inexpensive and highly active electrocatalysts are desirable for efficient urea electrocatalysis. Herein, carbon‐doped heterostructured Ni2P (C@Ni2P) nanocomposites are developed via a one‐step hydrothermal approach with surface engineering of peapod‐assisted nanorods (NRs‐peapod) and nanoparticles (NPs). The catalytic activities of the as‐prepared hybrids are studied with a robust emphasis on the surface structure–activity relationship. As expected, the embedded carbon matrices improve the electronic configuration of the resultant hybrids. Besides, the collaborative effects of both Ni2P and carbon platforms reduce the electron pathways and further promote the urea electro‐oxidation process. In particular, C@Ni2P NRs‐peapod present higher activity in terms of the oxidation current density and onset potential compared with C@Ni2P NPs, which is largely assigned to the corresponding high surface area and hence accessible electroactive centers. Moreover, the longitudinal orientation of the NRs‐peapod with a preferable porous feature may decrease the charge transfer resistance and facilitate electron/ion diffusion along the electrode surface and at electrode/electrolyte interfaces, indicating their potential for future utilization in direct urea fuel cells.

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Enhanced performance and electrocatalytic kinetics of Ni-Mo/graphene nanocatalysts towards alkaline urea oxidation reaction

Cited by 120 publications

References 26 publications

Nanosheets of CuCo2O4 As a High-Performance Electrocatalyst in Urea Oxidation

Nanosheets of CuCo2O4 As a High-Performance Electrocatalyst in Urea Oxidation

Heterostructured Nickel‐Cobalt Selenide Immobilized onto Porous Carbon Frameworks as an Advanced Anode Material for Urea Electrocatalysis

Shape‐Dependent Electrocatalytic Activity of Carbon Reinforced Ni₂P Hybrids Toward Urea Electrocatalysis

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Enhanced performance and electrocatalytic kinetics of Ni-Mo/graphene nanocatalysts towards alkaline urea oxidation reaction

Cited by 120 publications

References 26 publications

Nanosheets of CuCo2O4 As a High-Performance Electrocatalyst in Urea Oxidation

Nanosheets of CuCo2O4 As a High-Performance Electrocatalyst in Urea Oxidation

Heterostructured Nickel‐Cobalt Selenide Immobilized onto Porous Carbon Frameworks as an Advanced Anode Material for Urea Electrocatalysis

Shape‐Dependent Electrocatalytic Activity of Carbon Reinforced Ni2P Hybrids Toward Urea Electrocatalysis

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Shape‐Dependent Electrocatalytic Activity of Carbon Reinforced Ni₂P Hybrids Toward Urea Electrocatalysis