Melt Infiltration: an Emerging Technique for the Preparation of Novel Functional Nanostructured Materials

Abstract

The rapidly expanding toolbox for design and preparation is a major driving force for the advances in nanomaterials science and technology. Melt infiltration originates from the field of ceramic nanomaterials and is based on the infiltration of porous matrices with the melt of an active phase or precursor. In recent years, it has become a technique for the preparation of advanced materials: nanocomposites, pore-confined nanoparticles, ordered mesoporous and nanostructured materials. Although certain restrictions apply, mostly related to the melting behavior of the infiltrate and its interaction with the matrix, this review illustrates that it is applicable to a wide range of materials, including metals, polymers, ceramics, and metal hydrides and oxides. Melt infiltration provides an alternative to classical gas-phase and solution-based preparation methods, facilitating in several cases extended control over the nanostructure of the materials. This review starts with a concise discussion on the physical and chemical principles for melt infiltration, and the practical aspects. In the second part of this contribution, specific examples are discussed of nanostructured functional materials with applications in energy storage and conversion, catalysis, and as optical and structural materials and emerging materials with interesting new physical and chemical properties. Melt infiltration is a useful preparation route for material scientists from different fields, and we hope this review may inspire the search and discovery of novel nanostructured materials.

MnOx‐loaded Mesoporous Silica for the Catalytic Oxidation of Formaldehyde. Effect of the Melt Infiltration Conditions on the Activity – Stability Behavior

“…Unexpectedly, a new type of MnO x NPs formed in an egg‐shell shape were generated by MIa when the Pluronic P123 is kept within the porosity for infiltration step. These results demonstrate that infiltration of the molten precursor can be accomplished within the unique nanospaces between the surfactant molecules and the silica walls, as already suggested in recent investigations . Mn 3 O 4 NPs appear to cover the walls of SBA‐15 mesopores while keeping the mesopores opened.…”

“…In the case of 30Mn‐MIc‐300, a shoulder is observed at higher temperature (T=435 °C). This could be explained by the presence of larger MnO 2 NPs located at the external surface of the silica grain, which are more difficult to be reduced . The more important formation of such large – external – NPs for 30Mn‐MIc‐300 is in agreement with the Mn loading limit, as it has been observed by HR‐TEM (Figure ).…”

Experimental Challenges in Studying Hydrogen Absorption in Ultrasmall Metal Nanoparticles

“…(Wilcoxon and Abrams, 2006;Roesler and Fischer, 2015). Another interesting technique is the melt infiltration of low temperature melting metals, such as Mg, into different porous carbon hosts (de Jongh and Eggenhuisen, 2013;Au et al, 2014). For both synthetic method many experimental parameters are plying a crucial role to ensure the stability toward coalescence and the high dispersion of such nanoparticles on the support: the porosity/surface chemistry of the support, the nature of metal precursor, the metal loading, and the synthesis conditions: temperature, reducing agent, etc.…”

Fabrication of mesoporous Al-SBA-15 as a methylene blue capturer via a spontaneous infiltration route

“…However, materials synthesized by impregnation tend to form metal oxide aggregations in the channels or on the external surface of the supports, which finally leads to blocked channels as well. 30 In the present study, we used the simple and facile solvent-free strategy to synthesize Al-incorporated SBA-15 materials (denoted GAx). [22][23][24] Metal species could be easily infiltrated and highly dispersed into SBA-15 by grinding precursor salts and mesoporous supports (template-free or template-containing) followed by calcinations.…”