scholarly journals Sol-Gel Biotemplating Route with Cellulose Nanocrystals to Design Photocatalyst Boosting the Hydrogen Generation

2020 ◽  
Author(s):  
cong wand ◽  
jian li ◽  
Erwan Paineau ◽  
Abdelghani Laachachi ◽  
Christophe Colbeau-Justin ◽  
...  
Keyword(s):  
Cellulose Nanocrystals ◽  
Hydrogen Generation ◽  
Light Harvesting ◽  
Sol Gel ◽  
Charge Carriers ◽  
Hybrid Films ◽  
One Pot ◽  
Chiral Nematic ◽  
Straightforward Method ◽  
Chiral Nematic Structure

<br> <div> <p>Light harvesting capability and charge carriers lifetime play critical roles in determining the photoefficency of photocatalyst. Herein, a one-pot method is proposed to design mesostructured TiO<sub>2</sub> materials by taking advantage of the ability of cellulose nanocrystals (CNC) to self-assemble into chiral nematic structures during solvent evaporation. After the xerogel formation, the as-obtained CNC/TiO<sub>2</sub> hybrid films exhibit a chiral nematic structure and tunable Bragg peak reflection, generating lamellar TiO<sub>2</sub> mesostructure after the biotemplate removal by calcination. More prominently, this straightforward method can be extended to couple TiO<sub>2</sub> with other metal oxides, improving the light-harvesting and charge carriers separation of these photocatalysts, in particular for boosting hydrogen generation. This foolproof approach opens new doors for the development of nanostructured materials for solar energy conversion and catalysis.<br></p></div>

scholarly journals Sol-Gel Biotemplating Route with Cellulose Nanocrystals to Design Photocatalyst Boosting the Hydrogen Generation

2020 ◽  
Author(s):  
cong wand ◽  
jian li ◽  
Erwan Paineau ◽  
Abdelghani Laachachi ◽  
Christophe Colbeau-Justin ◽  
...  
Keyword(s):  
Cellulose Nanocrystals ◽  
Hydrogen Generation ◽  
Light Harvesting ◽  
Sol Gel ◽  
Charge Carriers ◽  
Hybrid Films ◽  
One Pot ◽  
Chiral Nematic ◽  
Straightforward Method ◽  
Chiral Nematic Structure

<br> <div> <p>Light harvesting capability and charge carriers lifetime play critical roles in determining the photoefficency of photocatalyst. Herein, a one-pot method is proposed to design mesostructured TiO<sub>2</sub> materials by taking advantage of the ability of cellulose nanocrystals (CNC) to self-assemble into chiral nematic structures during solvent evaporation. After the xerogel formation, the as-obtained CNC/TiO<sub>2</sub> hybrid films exhibit a chiral nematic structure and tunable Bragg peak reflection, generating lamellar TiO<sub>2</sub> mesostructure after the biotemplate removal by calcination. More prominently, this straightforward method can be extended to couple TiO<sub>2</sub> with other metal oxides, improving the light-harvesting and charge carriers separation of these photocatalysts, in particular for boosting hydrogen generation. This foolproof approach opens new doors for the development of nanostructured materials for solar energy conversion and catalysis.<br></p></div>

scholarly journals A sol–gel biotemplating route with cellulose nanocrystals to design a photocatalyst for improving hydrogen generation

2020 ◽  
Vol 8 (21) ◽  
pp. 10779-10786 ◽  
Author(s):  
Cong Wang ◽  
Jian Li ◽  
Erwan Paineau ◽  
Abdelghani Laachachi ◽  
Christophe Colbeau-Justin ◽  
...  
Keyword(s):  
Charge Carrier ◽  
Cellulose Nanocrystals ◽  
Carrier Lifetime ◽  
Hydrogen Generation ◽  
Light Harvesting ◽  
Sol Gel ◽  
Charge Carrier Lifetime

Light harvesting capability and charge carrier lifetime play critical roles in determining the photoefficiency of a photocatalyst.

scholarly journals Concentric chiral nematic polymeric fibers from cellulose nanocrystals

2021 ◽  
Author(s):  
Arash Momeni ◽  
Christopher M. Walters ◽  
Yi-Tao Xu ◽  
Wadood Y. Hamad ◽  
Mark J. MacLachlan
Keyword(s):  
Cellulose Nanocrystals ◽  
Liquid Crystalline ◽  
Capillary Tube ◽  
Single Domain ◽  
Cellulose Nanocrystal ◽  
Polymeric Fibers ◽  
Chiral Nematic ◽  
Chiral Nematic Structure ◽  
Crystalline Suspension

A cellulose nanocrystal liquid crystalline suspension was mixed with monomers and confined to a capillary tube. After photopolymerization, a fiber with a single-domain concentric chiral nematic structure throughout the length of the fiber was obtained.

scholarly journals Enhanced Photogenerated Charge Carriers and Photocatalytic Activity of Biotemplated Mesoporous TiO2 Films with a Chiral Nematic Structure

2019 ◽  
Vol 31 (13) ◽  
pp. 4851-4863 ◽  
Author(s):  
Getaneh Diress Gesesse ◽  
Chunyu Li ◽  
Erwan Paineau ◽  
Youssef Habibi ◽  
Hynd Remita ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Mesoporous Tio2 ◽  
Charge Carriers ◽  
Tio2 Films ◽  
Chiral Nematic ◽  
Chiral Nematic Structure ◽  
Mesoporous Tio2 Films

scholarly journals Flexible and Structural Coloured Composite Films from Cellulose Nanocrystals/Hydroxypropyl Cellulose Lyotropic Suspensions

Crystals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 122 ◽  
Author(s):  
Diogo V. Saraiva ◽  
Ricardo Chagas ◽  
Beatriz M. de Abreu ◽  
Cláudia N. Gouveia ◽  
Pedro E. S. Silva ◽  
...  
Keyword(s):  
Cellulose Nanocrystals ◽  
Near Infrared ◽  
Colloidal Suspension ◽  
Aqueous Suspension ◽  
Composite Films ◽  
Helical Structure ◽  
Infrared Region ◽  
Hydroxypropyl Cellulose ◽  
Chiral Nematic ◽  
Chiral Nematic Structure

Lyotropic colloidal aqueous suspensions of cellulose nanocrystals (CNCs) can, after solvent evaporation, retain their chiral nematic arrangement. As water is removed the pitch value of the suspension decreases and structural colour-generating films, which are mechanically brittle in nature, can be obtained. Increasing their flexibility while keeping the chiral nematic structure and biocompatible nature is a challenging task. However, if achievable, this will promote their use in new and interesting applications. In this study, we report on the addition of different amounts of hydroxypropyl cellulose (HPC) to CNCs suspension within the coexistence of the isotropic-anisotropic phases and infer the influence of this cellulosic derivative on the properties of the obtained solid films. It was possible to add 50 wt.% of HPC to a CNCs aqueous suspension (to obtain a 50/50 solids ratio) without disrupting the LC phase of CNCs and maintaining a left-handed helical structure in the obtained films. When 30 wt.% of HPC was added to the suspension of CNCs, a strong colouration in the film was still observed. This colour shifts to the near-infrared region as the HPC content in the colloidal suspension increases to 40 wt.% or 50 wt.% The all-cellulosic composite films present an increase in the maximum strain as the concentration of HPC increases, as shown by the bending experiments and an improvement in their thermal properties.

scholarly journals Heterogeneous Hybrid Nanocomposite Based on Chitosan/Magnesia Hybrid Films: Ecofriendly and Recyclable Solid Catalysts for Organic Reactions

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3583
Author(s):  
Metwally Madkour ◽  
Khaled D. Khalil ◽  
Fakhreia A. Al-Sagheer
Keyword(s):  
Heterogeneous Catalysts ◽  
Sol Gel ◽  
Analytical Techniques ◽  
Hybrid Films ◽  
One Pot ◽  
Solid Catalysts ◽  
Force Microscopy ◽  
Chitosan Matrix ◽  
Atomic Force ◽  
Sol Gel Process

Chitosan/magnesia hybrid films (CS-Mg) have been prepared via sol-gel process and employed as heterogeneous catalysts. An in situ generation of a magnesia network in the chitosan matrix was performed through hydrolysis/condensation reactions of magnesium ethoxide. The synthesized hybrid films were characterized using various analytical techniques, such as X-ray photo-electron spectroscopy (XPS), field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The hybrid films display excellent catalytic activities in Michael and Knoevenagel reactions via one pot or solvent-free approaches under microwave irradiation conditions. Chitosan/magnesia hybrid films, catalysed pyrimidine, benzochromene, coumarin and arylidene-malononitriles derivatives formation reactions occurred with highly efficient yields of 97%, 92%, 86% and 95% respectively. Due to the fact that the films are durable and insoluble in common organic solvents, they were easily separated and can be recycled up to five times without a considerable loss of their catalytic activity.

Aerogel materials with periodic structures imprinted with cellulose nanocrystals

Nanoscale ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 3805-3812 ◽  
Author(s):  
Yi-Tao Xu ◽  
Yiling Dai ◽  
Thanh-Dinh Nguyen ◽  
Wadood Y. Hamad ◽  
Mark J. MacLachlan
Keyword(s):  
Cellulose Nanocrystals ◽  
Periodic Structures ◽  
Cellulose Nanocrystal ◽  
Chiral Nematic ◽  
Chiral Nematic Structure

Periodic aerogels with a chiral nematic structure were obtained through the solidification of phase-separated cellulose nanocrystal suspensions.

Macrocellular Titanosilicate Monoliths as Highly Efficient Structured Olefin Epoxidation Catalysts

2019 ◽  
Author(s):  
Valentin Smeets ◽  
Ludivine van den Biggelaar ◽  
Tarek Barakat ◽  
Eric M. Gaigneaux ◽  
Damien Debecker
Keyword(s):  
Sol Gel ◽  
Silica Matrix ◽  
Flow Mode ◽  
Tetrahedral Coordination ◽  
Excellent Performance ◽  
One Pot ◽  
Templating Method ◽  
Porous Texture ◽  
Internal Phase ◽  
Epoxidation Of Cyclohexene

Self-standing macrocellular titanosilicate monolith foams are obtained using a one-pot sol-gel route and show excellent performance in the epoxidation of cyclohexene. Thanks to the High Internal Phase Emulsion (HIPE) templating method, the materials feature a high void fraction, a hierarchically porous texture and good mechanical strength. Highly dispersed Ti species can be incorporated in tetrahedral coordination the silica matrix. These characteristics allow the obtained ‘SiTi(HIPE)’ materials to reach high catalytic turnover in the epoxidation of cyclohexene. The monoliths can advantageously be used to run the reaction in continuous flow mode.<br>

scholarly journals Nanocomposites of Polyaniline and Cellulose Nanocrystals Prepared in Lyotropic Chiral Nematic Liquid Crystals

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Dawei Zhang ◽  
Lihong Zhang ◽  
Bingzhe Wang ◽  
Guangzhe Piao
Keyword(s):  
Liquid Crystals ◽  
Cellulose Nanocrystals ◽  
Nematic Liquid Crystals ◽  
Weight Ratio ◽  
Asymmetric Reaction ◽  
Reaction Field ◽  
Electron Microscopies ◽  
Chiral Nematic ◽  
Before And After

Stable lyotropic chiral nematic liquid crystals (N*-LCs) of cellulose nanocrystals (CNs) were prepared via hydrolysis using sulfuric acid. The lyotropic N*-LCs were used as an asymmetric reaction field to synthesize polyaniline (PANI) onto CNs by in situ polymerization. As a primary step, we examined the mesophase transition of the N*-LCs of CNs suspension before and after in situ polymerization of aniline (ANI) by polarizing optical microscopy. The structure of nanocomposites of PANI/CNs was investigated at a microscopic level using Fourier transform infrared spectroscopy and X-ray diffraction. Influence of the CNs-to-ANI ratio on the morphology of the nanocomposites was also investigated at macroscopic level by scanning electron and transmission electron microscopies. It is found that the weight ratio of CNs to aniline in the suspension significantly influenced the size of the PANI particles and interaction between CNs and PANI. Moreover, electrical properties of the obtained PANI/CNs films were studied using standard four-probe technique. It is expected that the lyotropic N*-LCs of CNs might be available for an asymmetric reaction field to produce novel composites of conjugated materials.

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