Spontaneously formed porous and composite materials

Abstract

In recent years, a number of routes to porous materials have been developed which do not involve the use of pre-formed templates or structure-directing agents. These routes are usually spontaneous, meaning they are thermodynamically downhill. Kinetic control, deriving from slow diffusion of certain species in the solid state, allows metastable porous morphologies rather than dense materials to be obtained. While the porous structures so formed are random, the average architectural features can be well-defined, and the porosity is usually highly interconnected. The routes are applicable to a broad range of functional inorganic materials. Consequently, the porous architectures have uses in energy transduction and storage, chemical sensing, catalysis, and photoelectrochemistry. This is in addition to more straightforward uses deriving from the pore structure, such as in filtration, as a structural material, or as a cell-growth scaffold. In this feature article, some of the methods for the creation of porous materials are described, including shape-conserving routes that lead to hierarchical macro/ mesoporous architectures. In some of the preparations, the resulting mesopores are aligned locally with certain crystallographic directions. The coupling between morphology and crystallography provides a macroscopic handle on nanoscale structure. Extension of these routes to create biphasic composite materials are also described.

Engineering macroporous composite materials using competitive adsorption in particle-stabilized foams

“…The performance of engineered porous composite materialswhether gauged by stability, reactivity, mechanical strength, or some other material property -is dictated not only by the nature of the constituents but also by their distribution within the solid matrix [16]. Current methods for manufacturing porous composite materials are, however, rather limited with respect to the control they offer over the distribution of material.…”

“…While the study of composite materials has largely been dominated by a focus on dense materials [2,3], porous composite materials have recently attracted considerable attention and have been identified for promising applications as bone scaffolds in biomedicine [4][5][6][7][8][9][10]; shielding layers in electrical engineering [11,12]; shock dissipators in structural engineering [13]; and as catalysts and filters in chemical engineering [14][15][16][17].…”

Sulfonated Porous Polymeric Nanofibers as an Efficient Solid Acid Catalyst for the Production of 5‐Hydroxymethylfurfural from Biomass

“…Aw ide range of strategies have been developed to design porous materials,w hich do not involve the use of templates or structuredirectinga gents. [15] In this context, porous organic polymers (POPs) are very demanding as one can tune the pore aperture and reactive functional groups,w hich are present as the building blocks of the respective POPs. [16] Aw ide range of related porousp olymeric materials such as porous aromatic frameworks, [17] conjugated microporous polymers, [18] porous organic Sustainable supplyo fe nergy is one of the biggest challenges today.T he conversion of energy from any abundant and renewable resources would be an ideal solution for this ever increasingdemandofsustainable energy.Biomass provides apotential energy alternative through the platform chemical 5-hydroxymethylfurfural (HMF), which is considered as asustainable source for liquid fuels and commodity chemicals.…”

Polydopamine nanotubes-templated synthesis of TiO2and its photocatalytic performance under visible light

“…Therefore, porous nanostructures have important applications as scaffolds for bio-, electro-and photocatalysts. [1][2][3][4][5] Porous carbon nanostructures as catalyst carriers have attracted considerable attention because of their good thermal and chemical stability, low cost, large surface area, and versatile fabrication methods. In particular, carbon scaffolds can improve catalyst properties signicantly.…”