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

Abstract

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.

Improving plasma sprayed Raney-type nickel–molybdenum electrodes towards high-performance hydrogen evolution in alkaline medium

“…Moreover, the enrichment of Al on the interface will cause peeling-off the coating, leading dust-like sediments and degradation of electrode performance. Conversely, the existence of Mo gives the electrode higher resistance to electrochemical corrosion 33 . Therefore, with homogenous distribution of Mo and presence of lower amount of aluminide phases, sample No.…”

Corrosion and Mechanical Properties of the Fe‐W‐Wo2 and Fe‐Mo‐MoO2 Nanocomposites

“…e formation of incompletely reduced oxides of refractory metals in situ in the cathode process follows from the mechanisms of electrodeposition of alloys proposed in [23]. In addition, their incorporation into the Fe-Mo(W) matrix is described in [12]. e use of pulse electrolysis (Figure 1(b)) contributes to the leveling of surface relief; the number of burrs is considerably decreased, and the coating becomes a little bit brighter.…”

“…However, in these works, no attention was paid to the study of Fe-Mo electrolytic alloys' corrosion and mechanical properties. e step mechanism of Fe-Mo alloys' electrodeposition from an alkaline solution containing Fe (III) ions and sorbitol was established [12]. e incorporation of molybdenum (IV) oxide into the coatings was shown.…”

Electrochemical synthesis of nanostructured super-alloys with valuable electrochemical, electrocatalytic and corrosion properties

“…1. Стан розвитку електрохімії суперсплавів 3d [6][7][8] Склад електроліту, наведений у роботі [30], було адаптовано для електроосадження бінарних Мо-вмісних сплавів. Для визначення впливу природи металу групи заліза на каталітичну активність цільових покриттів (сплави, збагачені нікелем, кобальтом, залізом) електрохімічні умови було підібрано так, щоб забезпечити осадження сплавів з подібним вмістом молібдену.…”