Controlling the primary particle evolution process towards silica monoliths with tunable hierarchical structure

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Hierarchical porous materials offer advantages in mass transport and surface area.
• Controlling pore structure across multiple length scales remains a challenge.
• Mesoporous silica monoliths are versatile platforms for various applications.

Purpose of the Study:

• To develop a new strategy for synthesizing hierarchical mesoporous silica monoliths.
• To control pore configuration from nanometer to millimeter scales.
• To investigate the structure-property relationships and potential applications.

Main Methods:

• Synthesis of hierarchical monoliths using triblock copolymer P123, hydroxyl carboxylic acid, and tetramethyl orthosilicate (TMOS) under weak acidic conditions.
• Adjustment of textural properties by controlling synthesis conditions.
• Characterization of pore size, pore volume, surface area, and pore shape.
• Evaluation of mechanical strength and application in filtering particulate matter and tobacco-specific nitrosamines (TSNA).

Main Results:

• Successfully synthesized hierarchical mesoporous silica monoliths with tunable pore structures across multiple length scales.
• Demonstrated control over primary particle morphology (sphere, noodle, prism, rods, bars) and their 3D arrangement.
• Achieved tunable mesoporous properties including pore size (5.5-10.6 nm), total pore volume (0.48-1.2 cm(3) g(-1)), and micropore surface area (47-334 m(2) g(-1)).
• Monoliths exhibited significant mechanical strength and efficacy in removing particulate matter and TSNA from tobacco smoke.

Conclusions:

• A facile and additive-free strategy for creating hierarchical mesoporous silica monoliths with controlled multi-level structures was established.
• The tunable textural properties and morphology-assisted functions highlight the potential of these materials in advanced filtration and separation technologies.
• The developed monoliths present a promising platform for addressing challenges in air purification and other fields requiring tailored porous materials.