Fabrication and characterization of hierarchical Mg/Ni/Al layered double hydroxide framework on aluminum foam

• Mg/Ni/Al layered double hydroxide (LDH) framework with hierarchical structure was successfully fabricated on the surface of Al foam by the in situ growth method.
• Two steps of synthesis process were carried out through preparation of thermodynamically unstable MgAl-LDH film on Al substrate and transformation of MgAl-LDH film to MgNiAl-LDH film.
• The higher concentration of Mg2+ than Ni2+ in parent solution was adopted in order to suppress the competitive effect of Ni2+.

A hierarchical Mg/Ni/Al layered double hydroxide (LDH) framework has been fabricated via the in situ crystallization process on aluminum foam (denoted as Mg/Ni/Al LDH/Al-foam). XRD and SEM confirm that the as-prepared Mg/Ni/Al LDH displays flowerlike microspheres (2–5 μm) composed of numerous LDH nanoplatelets (1–2 μm in width and ~50 nm in thickness). The BET analysis shows that the specific surface area of the Mg/Ni/Al LDH is 96.8 m²/g owing to its hierarchical structure, which is much higher than that of the traditional bi-metal Mg/Al LDH. Two steps of the synthesis strategy were carried out in order to eliminate the competitive difference between cations composed of LDH. The present work provided a new strategy for a scale-up synthesis of well-crystallized tri-metal LDH materials on metal substrate by the in situ crystallization technique.