Factorial design in the electrodeposition of Co-Mo coatings and their evaluations for hydrogen evolution reaction

Casciano, Paulo N.S.; Benevides, Ramon L.; Santana, Renato Alexandre Costa de; Correia, Adriana N.; Lima‐Neto, Pedro de

doi:10.1016/j.jallcom.2017.06.282

Cited by 38 publications

(13 citation statements)

References 51 publications

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“…Effect of electrolyte temperature. It is known that the temperature of alkaline bath plays an important role on the increase of the catalytic activity of W(Mo)-based cathodes towards the HER [11,87]. Hence, the electrodeposited Ni-29at.%W, Co-33at.%W and Fe-30at.%W alloy electrodes that demonstrate the higher apparent catalytic activity were tested at the temperature range from 25 to 65 C by applying 10 C increments.…”

Section: Electrocatalytic Hydrogen Evolution On Ni-w Co-w and Fe-w Cmentioning

confidence: 99%

Electrodeposited tungsten-rich Ni-W, Co-W and Fe-W cathodes for efficient hydrogen evolution in alkaline medium

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Sobczak

et al. 2019

Electrochimica Acta

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The search of active, stable and cost-effective non-noble electrocatalysts for hydrogen evolution reaction (HER) is essential for sustainable energy systems. In this study, the electrodeposited Ni-W, CoW and FeW coatings having 5e30 at.% of W were examined as an alternative electrocatalysts for hydrogen evolution. The electrocatalytic efficiency of the electrodes was investigated on the basis of electrochemical data obtained from steady-state polarization technique in 30 wt% NaOH solution. It was found that with increasing of tungsten content in the deposits up to ~30 at.% a crystal-to-ultra-nanocrystalline transition takes place and the crystal grain size decreases up to 2e4 nm. The high content of W leads to course-grained coatings. These morphological and structural changes showed remarkable impact on the catalytic activity. The maximum catalytic performance was obtained for ultra-nanocrystalline W coatings. Among them the Ni-29at.%W demonstrated the highest apparent exchange current density (ECD) at the room temperature, i.e. 0.55 mA cm À2 , thus indicating more favorable hydrogen reduction. A significant improvement of catalytic activity of all tested cathodes with increasing the temperature of NaOH solution was noticed. Among investigated Co-33at.%W, Fe-30at.%W and Ni-29at.%W cathodes, the last one showed the best performance towards HER (ECD ¼ 14.5 mA cm À2 at 65 C).

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Section: Electrocatalytic Hydrogen Evolution On Ni-w Co-w and Fe-w Cmentioning

confidence: 99%

Electrodeposited tungsten-rich Ni-W, Co-W and Fe-W cathodes for efficient hydrogen evolution in alkaline medium

Vernickaite

Цынцару

Sobczak

et al. 2019

Electrochimica Acta

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“…For the Fe-Mo (also Fe-W) system, the Mössbauer spectroscopy supports this presumption and suggests that deposits having more than 17 at.% of refractory metal consists of a mixture of molybdenum solid solution in α-Fe and intermetallic phases, e.g., Fe3Mo, Fe2Mo [55,56]. In the case of the Co-Mo alloy, some of the studies reported that a Mo solid solution in cobalt and intermetallic Co3Mo is formed [36,57].…”

Section: Design Of Mo-rich Alloys Coatingsmentioning

confidence: 77%

“…An improvement of catalytic activity for the HER with the operation temperature, as is desired for practical industrial alkaline electrolysis has been reported [36,42]. Accordingly, in the present study, the electrodeposited alloy electrodes were tested at temperatures ranging from 25 to 65 °C by applying 10 °C increments.…”

Section: Parametermentioning

confidence: 98%

“…Therefore, researchers' efforts were directed to optimize the plating bath vs. deposition conditions in order to obtain Mo-rich alloys as effective catalysts for the HER. It was shown that electrodeposition from ammonia based aqueous solutions produces Mo alloys with up tõ 41 at.% of Mo [32][33][34][35][36]. Coatings containing more than 40 at.% Mo have been electrodeposited from ammonium-citrate solution in the presence of imidazolium-based ionic liquids as an additive [37].…”

Section: Introductionmentioning

confidence: 99%

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Design of Highly Active Electrodes for Hydrogen Evolution Reaction Based on Mo-Rich Alloys Electrodeposited from Ammonium Acetate Bath

et al. 2019

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The given research was driven by prospects to design Mo-rich coatings with iron group metals electrodeposited from a highly saturated ammonium acetate bath. The obtained coatings could be employed as prominent electrodes for the hydrogen evolution reaction (HER). It was found that the Mo content in Ni–Mo alloys can be tuned from 30 to 78 at.% by decreasing the molar ratio [Ni(II)]:[Mo(VI)] in the electrolyte from 1.0 to 0.25 and increasing the cathodic current density from 30 to 100 mA/cm2. However, dense cracks and pits are formed due to hydrogen evolution at high current densities and that diminishes the catalytic activity of the coating for HER. Accordingly, smoother and crack-free Ni–54 at.% Mo, Co–52 at.% Mo and Fe–54 at.% Mo alloys have been prepared at 30 mA/cm2. Their catalytic behavior for HER has been investigated in a 30 wt.% NaOH solution at temperatures ranging from 25 to 65 °C. A significant improvement of electrocatalytic activity with increasing bath temperature was noticed. The results showed that the sequence of electrocatalytic activity in alkaline media decreases in the following order: Co–52 at.% Mo > Ni–54 at.% Mo > Fe–54 at.% Mo. These peculiarities might be linked with different catalytic behavior of formed intermetallics (and active sites) in electrodeposited alloys. The designed electrodeposited Mo-rich alloys have a higher catalytic activity than Mo and Pt cast metals.

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“…Despite this, the origination of cracks in Co-Mo-Zr coatings is independent of the refractory components content as well as of current density. Many studies have paid attention to the cracking of binary and ternary cobalt and molybdenum alloys [30,31]. A possible cause of the coatings fracturing can be the difference in the crystal lattice types of the alloying metals.…”

Section: ]mentioning

confidence: 99%

CORROSION BEHAVIOR OF THE ELECTROLYTIC TERNARY COBALT ALLOYS WITH Mo(W) AND Zr IN ALKALINE SOLUTION

et al. 2019

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The ternary Co–Mo–W(Zr) coatings with total content of refractory metals of 30–40 wt.%, and Co–W–Zr alloys (12–26 wt.%) are deposited from pyrophosphate-citrate electrolytes in pulse regime. The composition of the coatings as well as the surface morphology depends on the current density. The X-ray diffraction patterns reflect the amorphous-and-crystalline ternary alloys structure. Phases of α-Co, Co–Mo intermetallic compounds, and traces of metallic molybdenum were detected in the Co–Mo–Zr coatings. Phase composition of Co–Mo–W deposits differs by emergence of Co7W6 phase and traces of metallic tungsten, and there is no metallic W in Co–W–Zr electrolytic alloys. The corrosion behavior of ternary coatings in alkaline medium studied by EIS shows that Co–Mo–Zr alloys are characterized by highest corrosion resistance among deposited coatings due to presence of metallic molybdenum and stoichiometric ZrO2 with both high electrical resistivity and chemical stability. The coatings Co–Mo–W and Co–Mo–Zr containing phases of Mo or W are characterized by higher corrosion resistance as compared with that without metallic molybdenum and tungsten. The cyclic voltammetry data confirm stability of ternary coatings in alkaline solution under anodic polarization. Such properties as well as the developed globular surface make materials promising for use as anodes in fuel cells in particular based on alkali electrolytes.

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Factorial design in the electrodeposition of Co-Mo coatings and their evaluations for hydrogen evolution reaction

Cited by 38 publications

References 51 publications

Electrodeposited tungsten-rich Ni-W, Co-W and Fe-W cathodes for efficient hydrogen evolution in alkaline medium

Electrodeposited tungsten-rich Ni-W, Co-W and Fe-W cathodes for efficient hydrogen evolution in alkaline medium

Design of Highly Active Electrodes for Hydrogen Evolution Reaction Based on Mo-Rich Alloys Electrodeposited from Ammonium Acetate Bath

CORROSION BEHAVIOR OF THE ELECTROLYTIC TERNARY COBALT ALLOYS WITH Mo(W) AND Zr IN ALKALINE SOLUTION

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