Stepwise Monomicelle Assembly for Highly Ordered Mesoporous TiO₂ Membranes with Precisely Tailored Mesophase and Porosity

Abstract

Mesoporous materials with crystalline frameworks have been acknowledged as very attractive materials in various applications. Nevertheless, due to the cracking issue during crystallization and incompatible hydrolysis and assembly, the precise control for crystalline mesoscale membranes is quite infertile. Herein, we presented an ingenious stepwise monomicelle assembly route for the syntheses of highly ordered mesoporous crystalline TiO2 membranes with delicately controlled mesophase, mesoporosity, and thickness. Such a process involves the preparation of monomicelle hydrogels and follows self-assembly by stepwise solvent evaporation, which enables the sensitive hydrolysis of TiO2 oligomers and dilatory micelle assembly to be united. In consequence, the fabricated mesoporous TiO2 membranes exhibit a broad flexibility, including tunable ordered mesophases (worm-like, hexagonal p6mm to body-centered cubic Im3̅m), controlled mesopore sizes (3.0–8.0 nm), and anatase grain sizes (2.3–8.4 nm). Besides, such mesostructured crystalline TiO2 membranes can be extended to diverse substrates (Ti, Ag, Si, FTO) with tailored thickness. The great mesoporosity of the in situ fabricated mesoscopic membranes also affords excellent pseudocapacitive behavior for sodium ion storage. This study underscores a novel pathway for balancing the interaction of precursors and micelles, which could have implications for synthesizing crystalline mesostructures in higher controllability.

Mesoporous TiO2 Single-Crystal Particles from Controlled Crystallization-Driven Mono-Micelle Assembly as an Efficient Photocatalyst

“…The hydrogels were fabricated according to the approach of refs and . In a typical synthesis, 1.6 g of F127 was added into a wide-mouth bottle containing 30 mL of THF, followed by a drop of 2.4 mL of acetic acid (AcOH) and 1.5 mL of concentrated hydrochloric acid (HCl).…”

Ordered Mesoporous Crystalline Frameworks Toward Promising Energy Applications

“…Among the many functional energy materials, mesoporous crystalline frameworks (MCFs) that have pore diameters between 2 and 50 nm and crystallized pore walls, have been acknowledged as promising for energy applications due to their spectacular physical properties. [13][14][15][16][17] To be specific, high specific surface areas and large pore volumes can afford substantially enhanced accessibilities, such as surface contact to adsorption reactants or electrodes. [18] Large pore sizes enable to better encapsulate guest molecules or accommodate mechanical strains during electrochemical cycling.…”

Evoking C2+ production from electrochemical CO2 reduction by the steric confinement effect of ordered porous Cu2O

“…Three-dimensional ordered porous (3DOP) materials, characterized by their well-dened pore arrangements, tunable pore sizes, and smooth mass transfer of the 3D interconnected pore channels, have demonstrated remarkable catalytic performance. [13][14][15][16][17][18][19] Employing hard templates, including mesoporous materials (e.g., mesoporous silica and carbon) 13,[19][20][21][22] and colloidal crystals (e.g., polystyrene and silica spheres), 20,[23][24][25][26][27][28][29] has been the most extensively explored method for fabricating 3DOP materials. Despite signicant efforts in this area, it remains a substantial challenge to achieve precise control over the nanoarchitectures within the templates to create 3DOP materials, especially for those beyond the well-studied silica-, carbon-and metal-organic framework (MOF)-based materials.…”

“…Three-dimensional ordered porous (3DOP) materials, characterized by their well-defined pore arrangements, tunable pore sizes, and smooth mass transfer of the 3D interconnected pore channels, have demonstrated remarkable catalytic performance. 13–19 Employing hard templates, including mesoporous materials ( e.g. , mesoporous silica and carbon) 13,19–22 and colloidal crystals ( e.g.…”