Keggin-Type H₅PMo₁₀V₂O₄₀ Intercalated MgAl-LDH: Structural Integrity and Bifunctional Electrocatalytic Activity

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Sustainable water electrolysis requires earth-abundant electrocatalysts with improved conductivity and durability.
• Discrete polyoxometalates (POMs) show promise but suffer from high solubility, limiting their use as heterogeneous catalysts.

Purpose of the Study:

• To develop a stable, earth-abundant bifunctional electrocatalyst for alkaline water splitting.
• To overcome the solubility limitations of POMs by integrating them into a robust host material.

Main Methods:

• A Keggin-type H5PMo10V2O40 POM was intercalated into MgAl layered double hydroxide (MgAl-LDH) using a formamide-assisted exfoliation-reassembly strategy.
• Structural characterization (XRD, BET) and density functional theory (DFT) calculations were employed.
• Electrocatalytic performance for hydrogen and oxygen evolution was evaluated in 1.0 M KOH.

Main Results:

• The POM@MgAl-LDH hybrid exhibited quantitative ion exchange and increased basal spacing, confirmed by structural analysis and DFT.
• The hybrid material possessed a high surface area (50.6 m2 g-1) and hierarchical porosity.
• The POM@MgAl-LDH demonstrated efficient bifunctional electrocatalysis with low overpotentials (215 mV for H2 evolution, 411 mV for O2 evolution at 10 mA cm-2) and excellent stability (>97% retention over 12 h).

Conclusions:

• Spatial confinement of POMs within the MgAl-LDH host effectively prevents dissolution and enhances catalytic activity.
• This strategy offers a practical route to nonprecious-metal bifunctional electrocatalysts for efficient alkaline water splitting.
• The developed hybrid material represents a significant advancement in sustainable energy technologies.