Nanoparticle-Based Aerogels and Their Prospective Future Applications

Eychmüller, Alexander

doi:10.1021/acs.jpcc.2c06382

Cited by 10 publications

(7 citation statements)

References 82 publications

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“…A novel class of materials with an interesting morphology are nanocrystal-based gel structures, which exhibit high porosity and combine physicochemical properties of the NCs with the size of bulk material. [25][26][27][28] Nanocrystal-based gel structures undergo a controlled destabilization of the ligandstabilized nanocrystal solution to form a 3D, highly porous network which retains the properties of the NC building blocks. As has already been shown, semiconductor NC-based networks, for example, CdSe, [29] CdS, [30] and CdSe/CdS, [31][32][33] can even exhibit improved and novel properties compared to the NCs in solution.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Photocatalytic Hydrogen Production of Semiconductor Nanocrystal‐Based Hydrogels

Schlenkrich

Lübkemann

Graf

et al. 2023

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Destabilization of a ligand‐stabilized semiconductor nanocrystal solution with an oxidizing agent can lead to a macroscopic highly porous self‐supporting nanocrystal network entitled hydrogel, with good accessibility to the surface. The previously reported charge carrier delocalization beyond a single nanocrystal building block in such gels can extend the charge carrier mobility and make a photocatalytic reaction more probable. The synthesis of ligand‐stabilized nanocrystals with specific physicochemical properties is possible, thanks to the advances in colloid chemistry made in the last decades. Combining the properties of these nanocrystals with the advantages of nanocrystal‐based hydrogels will lead to novel materials with optimized photocatalytic properties. This work demonstrates that CdSe quantum dots, CdS nanorods, and CdSe/CdS dot‐in‐rod‐shaped nanorods as nanocrystal‐based hydrogels can exhibit a much higher hydrogen production rate compared to their ligand‐stabilized nanocrystal solutions. The gel synthesis through controlled destabilization by ligand oxidation preserves the high surface‐to‐volume ratio, ensures the accessible surface area even in hole‐trapping solutions and facilitates photocatalytic hydrogen production without a co‐catalyst. Especially with such self‐supporting networks of nanocrystals, the problem of colloidal (in)stability in photocatalysis is circumvented. X‐ray photoelectron spectroscopy and photoelectrochemical measurements reveal the advantageous properties of the 3D networks for application in photocatalytic hydrogen production.

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Section: Introductionmentioning

confidence: 99%

Investigation of the Photocatalytic Hydrogen Production of Semiconductor Nanocrystal‐Based Hydrogels

Schlenkrich

Lübkemann

Graf

et al. 2023

Small

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“…Non-aqueous or non-hydrolytic [ 8 , 9 , 10 , 11 ] and non-oxide [ 12 , 13 ] Sol–Gel systems have also been reported. The so-called non-hydrolytic routes frequently refer to oxidic products, which may be used for similar applications as oxide products derived from hydrolytic routes; these include catalyst supports [ 14 ], optical materials [ 15 ], or aerogels [ 16 , 17 , 18 ], among many others [ 4 , 5 , 6 , 7 , 8 , 9 ].…”

Section: Introductionmentioning

confidence: 99%

A Non-Hydrolytic Sol–Gel Route to Organic-Inorganic Hybrid Polymers: Linearly Expanded Silica and Silsesquioxanes

Krupinski

Wagler

Brendler

et al. 2023

Gels

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Condensation reactions of chlorosilanes (SiCl4 and CH3SiCl3) and bis(trimethylsilyl)ethers of rigid, quasi-linear diols (CH3)3SiO–AR–OSi(CH3)3 (AR = 4,4′-biphenylene (1) and 2,6-naphthylene (2)), with release of (CH3)3SiCl as a volatile byproduct, afforded novel hybrid materials that feature Si–O–C bridges. The precursors 1 and 2 were characterized using FTIR and multinuclear (1H, 13C, 29Si) NMR spectroscopy as well as single-crystal X-ray diffraction analysis in case of 2. Pyridine-catalyzed and non-catalyzed transformations were performed in THF at room temperature and at 60 °C. In most cases, soluble oligomers were obtained. The progress of these transsilylations was monitored in solution with 29Si NMR spectroscopy. Pyridine-catalyzed reactions with CH3SiCl3 proceeded until complete substitution of all chlorine atoms; however, no gelation or precipitation was found. In case of pyridine-catalyzed reactions of 1 and 2 with SiCl4, a Sol–Gel transition was observed. Ageing and syneresis yielded xerogels 1A and 2A, which exhibited large linear shrinkage of 57–59% and consequently low BET surface area of 10 m2⋅g−1. The xerogels were analyzed using powder-XRD, solid state 29Si NMR and FTIR spectroscopy, SEM/EDX, elemental analysis, and thermal gravimetric analysis. The SiCl4-derived amorphous xerogels consist of hydrolytically sensitive three-dimensional networks of SiO4-units linked by the arylene groups. The non-hydrolytic approach to hybrid materials may be applied to other silylated precursors, if the reactivity of the corresponding chlorine compound is sufficient.

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“…Noble metal aerogels assembled from colloidal nanoparticles have attracted considerable attention over the past decade. , The controlled assembly of starting nanoparticles of a specific size and shape into a highly porous network enables the creation of a wide range of novel materials with desired composition and specific properties such as electrical conductivity, catalytic activity, and increased permeability due to high porosity. − The applicability of noble metal aerogels for sensing, photonics, catalysis, and detection has already been demonstrated and summarized in recent reports. − ,, …”

Section: Introductionmentioning

confidence: 99%

“…3−5 The applicability of noble metal aerogels for sensing, photonics, catalysis, and detection has already been demonstrated and summarized in recent reports. [1][2][3]6,7 Despite their many advantages, the broad practical application of metal nanoparticle aerogels remains a challenge. One of the hindering factors is the high production costs, as special drying processes, such as supercritical or freeze-drying, are required to ensure the high porosity of the aerogel.…”

Section: ■ Introductionmentioning

confidence: 99%

Porous Thin Films with Large Specific Surface Area on the Basis of Spray-Coated Metal Aerogels

Khavlyuk,

Shamraienko,

Tenhagen

et al. 2023

J. Phys. Chem. C

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The preparation of aerogels in the form of thin films deposited on a substrate (e.g., as an electrode material) is an attractive but challenging task. Such thin films are expected to combine the highly porous gel nanostructure, good mechanical stability, and a remarkably high specific surface area with efficient charge-carrier transport via the interconnected nanoparticle chains. All together, they make them attractive for the fabrication of (electro)catalysts or sensors for microfluidics, flexible electrodes for microelectronics, soft electrodes compatible with a stress-sensitive bioenvironment, etc. In this work, thin aerogel films of colloidal Pd and PtNi building blocks were prepared from the corresponding wet gels using a spray technique. The films were fabricated on substrates of around 1.5 cm2. During the modification of the substrates, the film thickness can be adjusted by controlling the ink content (flow rate, gas pressure, and temperature) and the number of spray cycles. In this way, both the electrical (down to R s = ∼0.2 kOhm/sq) and optical parameters of the thin porous films can be tuned. Comparative studies of the pore and surface structures of the films have confirmed their integrity and the highly porous structure typical for aerogels. In perspective, spray-coated aerogels can be easily adapted to industrial applications because upscaling is possible and expensive equipment such as supercritical or freeze-dryers is not required. It is important to note that the spray-coating technique is applicable through a mask or can be converted to inkjet printing, which allows for the desired micropatterning of aerogel thin films.

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Nanoparticle-Based Aerogels and Their Prospective Future Applications

Cited by 10 publications

References 82 publications

Investigation of the Photocatalytic Hydrogen Production of Semiconductor Nanocrystal‐Based Hydrogels

Investigation of the Photocatalytic Hydrogen Production of Semiconductor Nanocrystal‐Based Hydrogels

A Non-Hydrolytic Sol–Gel Route to Organic-Inorganic Hybrid Polymers: Linearly Expanded Silica and Silsesquioxanes

Porous Thin Films with Large Specific Surface Area on the Basis of Spray-Coated Metal Aerogels

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