A hybrid of NiMo-Mo2C/C as non-noble metal electrocatalyst for hydrogen evolution reaction in an acidic solution

Zhang, Yan; Wang, Yanhui; Jia, Shaopei; Xu, Hanqing; Zang, Jianbing; Lu, Jing; Xu, Xipeng

doi:10.1016/j.electacta.2016.11.031

Cited by 55 publications

(18 citation statements)

References 47 publications

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“…The double‐layer capacitance ( C dl , mF cm −2 ) is represented by a constant phase element (CPE 1 , F s n−1 cm −2 ) due to the deviation of C dl from ideal capacitive behavior [64,65] . In all three models the time constant associated with R ct ( τ 1 = C dl ×R ct , s) is considered to be related to the charge transfer kinetics [8,31] …”

Section: Experimental and Simulation Sectionmentioning

confidence: 99%

“…[64,65] In all three models the time constant associated with R ct (τ 1 = C dl × R ct , s) is considered to be related to the charge transfer kinetics. [8,31] The two time constant models are applicable in different situations and the parameters R h and CPE 2 (F s nÀ 1 cm À 2 ) have a different physical interpretation, depending on which model is used. The parallel model (Figure 12b) corresponds to the full description of the HER kinetics, and the aforementioned parameters correspond to hydrogen adsorption part of the kinetics.…”

Section: Impedance Data Collection and Analysismentioning

confidence: 99%

“…NiMo alloys are typical earth‐abundant HER electrocatalysts and can potentially replace Pt because of their low overpotential over the entire pH range [7−10] . However, it is still not clear if the low HER overpotential is caused by their high intrinsic catalytic activities or by extrinsic factors such as increased surface area or mass loading, [11,12] which would have cost implications for large scale hydrogen production.…”

Section: Introductionmentioning

confidence: 99%

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Understanding the Hydrogen Evolution Reaction Kinetics of Electrodeposited Nickel‐Molybdenum in Acidic, Near‐Neutral, and Alkaline Conditions

et al. 2021

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Nickel‐molybdenum (NiMo) alloys can be a possible alternative to platinum as hydrogen evolution reaction (HER) catalysts because of the superior HER activity. However, the superior HER activity and the pH‐dependent kinetics are not currently fully understood. Herein, we present a study of HER kinetics and mechanisms of NiMo in alkaline, near‐neutral and acidic media by combining voltammetry measurements with electrochemical impedance spectroscopy and a microkinetic model. The results indicate that, compared to Ni, NiMo has significantly higher active surface area and intrinsic HER activity. In the subsequent measurements, we demonstrated that different from the existing explanations to the HER mechanisms for NiMo, the HER process in acidic, near‐neutral, and alkaline media is controlled by the Heyrovsky step. Our results show that increasing pH increases the hydrogen coverage, which increases the Tafel‐slope at low overpotentials, eventually resulting in only a single Tafel slope, which would commonly be interpreted as a Volmer‐limited reaction. Furthermore, the studies of thickness effect on HER kinetics show that the HER kinetics of NiMo are thickness‐dependent. In phosphate buffer, the increase in thickness did not significantly increase the double‐layer capacitance, but simulations with the microkinetic model indicate that the active surface area still increased similarly to other electrolytes, which is likely related to the type of electrolyte used.

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Section: Experimental and Simulation Sectionmentioning

confidence: 99%

Section: Impedance Data Collection and Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Understanding the Hydrogen Evolution Reaction Kinetics of Electrodeposited Nickel‐Molybdenum in Acidic, Near‐Neutral, and Alkaline Conditions

et al. 2021

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“…As shown in Figure b, the Ni 2p 3/2 and Ni 2p 1/2 peaks appear at 853.8 and 870.8 eV with a splitting of 17 eV, demonstrating the formation of metallic Ni atoms in Ru 1 Ni 1 ‐NCNFs. Furthermore, Ni 2p 3/2 and Ni 2p 1/2 signals at 856.3 and 874.4 eV with their corresponding satellite peaks at 860.8 and 880.8 eV suggest the oxidation of some surface of Ni atoms to NiO . It is worth noting that Ni 2+ species can effectively boost water dissociation to H* and that Ru can promote the combination of H* to H 2 through a synergistic effect .…”

mentioning

confidence: 92%

RuNi Nanoparticles Embedded in N‐Doped Carbon Nanofibers as a Robust Bifunctional Catalyst for Efficient Overall Water Splitting

et al. 2019

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Developing high‐performance, low‐cost, and robust bifunctional electrocatalysts for overall water splitting is extremely indispensable and challenging. It is a promising strategy to couple highly active precious metals with transition metals as efficient electrocatalysts, which can not only effectively reduce the cost of the preparation procedure, but also greatly improve the performance of catalysts through a synergistic effect. Herein, Ru and Ni nanoparticles embedded within nitrogen‐doped carbon nanofibers (RuNi‐NCNFs) are synthesized via a simple electrospinning technology with a subsequent carbonization process. The as‐formed RuNi‐NCNFs represent excellent Pt‐like electrocatalytic activity for the hydrogen evolution reaction (HER) in both alkaline and acidic conditions. Furthermore, the RuNi‐NCNFs also exhibit an outstanding oxygen evolution reaction (OER) activity with an overpotential of 290 mV to achieve a current density of 10 mA cm−2 in alkaline electrolyte. Strikingly, owing to both the HER and OER performance, an electrolyzer with RuNi‐NCNFs as both the anode and cathode catalysts requires only a cell voltage of 1.564 V to drive a current density of 10 mA cm−2 in an alkaline medium, which is lower than the benchmark of Pt/C||RuO2 electrodes. This study opens a novel avenue toward the exploration of high efficient but low‐cost electrocatalysts for overall water splitting.

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“…In addition, the timing current measurement under 1.518 V in water–urea splitting indicated that s-350||s-350 is able to maintain high current density within 25 h of operation (Figure 7D). Its high stability was confirmed, and the inset of Figure 7D shows the fluctuation of current density around the 20th hour, which can be attributed to the accumulation and release of the remaining bubbles on the electrode surface [48].…”

Section: Resultsmentioning

confidence: 99%

Nanostructured Nickel Nitride with Reduced Graphene Oxide Composite Bifunctional Electrocatalysts for an Efficient Water-Urea Splitting

et al. 2019

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A three-dimensional nickel nitride with reduced graphene oxide composite on nickel foam (s-X, where s represents Ni3N/rGO@NF and the annealing temperature X can be 320, 350, or 380) electrode has been fabricated through a facile method. We demonstrate that s-350 has excellent urea oxidation reaction (UOR) activity, with a demanded potential of 1.342 V to reach 10 mA/cm2 and bears high hydrogen evolution reaction (HER) activity. It provides a low overpotential of 124 mV at 10 mA/cm2, which enables the successful construction of its two-electrode alkaline electrolyzer (s-350||s-350) for water–urea splitting. It merely requires a voltage of 1.518 V to obtain 100 mA/cm2 and is 0.145 V lower than that of pure water splitting. This noble metal-free bifunctional electrode is regarded as an inexpensive and effective water–urea electrolysis assisted hydrogen production technology, which is commercially viable.

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A hybrid of NiMo-Mo2C/C as non-noble metal electrocatalyst for hydrogen evolution reaction in an acidic solution

Cited by 55 publications

References 47 publications

Understanding the Hydrogen Evolution Reaction Kinetics of Electrodeposited Nickel‐Molybdenum in Acidic, Near‐Neutral, and Alkaline Conditions

Understanding the Hydrogen Evolution Reaction Kinetics of Electrodeposited Nickel‐Molybdenum in Acidic, Near‐Neutral, and Alkaline Conditions

RuNi Nanoparticles Embedded in N‐Doped Carbon Nanofibers as a Robust Bifunctional Catalyst for Efficient Overall Water Splitting

Nanostructured Nickel Nitride with Reduced Graphene Oxide Composite Bifunctional Electrocatalysts for an Efficient Water-Urea Splitting

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