Design of Transition Metal Oxide and Hybrid Mesoporous Materials

2002 ◽  
Vol 728 ◽  
Author(s):  
Clément Sanchez ◽  
Eduardo L. Crepaldi ◽  
Anne Bouchara ◽  
Florence Cagnol ◽  
David Grosso ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Oxide ◽  
High Surface ◽  
High Surface Area ◽  
Directed Assembly ◽  
Optical Quality ◽  
Hybrid Thin Films ◽  
Poly Ethylene ◽  
Inorganic Framework ◽  
Hybrid Mesoporous Materials

AbstractMesostructured transition metal (Ti, Zr, V, Al and Ce-Zr) oxide-based hybrid thin films, templated by poly(ethylene oxide)-based surfactants or block copolymers, have been prepared reproducibly, displaying 2D-hexagonal (p6m) or 2D-centred rectangular (c2m) structure. By carefully adjusting the variables involved it is possible to combine both high organisation and excellent optical quality. TiO2 and ZrO2-based materials show thermal stability up to 400-550°C. The elimination of the template can be conducted efficiently and gives rise to high surface area mesoporous films. For the other metal oxide hybrids the inorganic framework is much more fragile, and requires a precise sequence of post-treatments to be stabilised. In addition, original and homogeneous macrotextures shaped with coral-like, helical or macroporous sieves morphologies have been obtained following a nanotectonic approach based on the template-directed assembly by poly-γ-benzyl-L-glutamate (PBLG) of organically functionalised CeO2 crystalline nanoparticles.

Intercalation of First Row Transition Metals inside Covalent-Organic Frameworks (COF): a Strategy to Fine Tune the Electronic Properties of Porous Crystalline Materials

2018 ◽  
Author(s):  
Srimanta Pakhira ◽  
Jose Mendoza-Cortes
Keyword(s):  
Transition Metal ◽  
Transition Metals ◽  
Electronic Properties ◽  
High Surface ◽  
Electronic Devices ◽  
High Surface Area ◽  
Main Role ◽  
Covalent Organic Frameworks ◽  
Porous Network ◽  
Crystalline Materials

<div>Covalent organic frameworks (COFs) have emerged as an important class of nano-porous crystalline materials with many potential applications. They are intriguing platforms for the design of porous skeletons with special functionality at the molecular level. However, despite their extraordinary properties, it is difficult to control their electronic properties, thus hindering the potential implementation in electronic devices. A new form of nanoporous material, COFs intercalated with first row transition metal is proposed to address this fundamental drawback - the lack of electronic tunability. Using first-principles calculations, we have designed 31 new COF materials <i>in-silico</i> by intercalating all of the first row transition metals (TMs) with boroxine-linked and triazine-linked COFs: COF-TM-x (where TM=Sc-Zn and x=3-5). This is a significant addition considering that only 187 experimentally COFs structures has been reported and characterized so far. We have investigated their structure and electronic properties. Specifically, we predict that COF's band gap and density of states (DOSs) can be controlled by intercalating first row transition metal atoms (TM: Sc - Zn) and fine tuned by the concentration of TMs. We also found that the $d$-subshell electron density of the TMs plays the main role in determining the electronic properties of the COFs. Thus intercalated-COFs provide a new strategy to control the electronic properties of materials within a porous network. This work opens up new avenues for the design of TM-intercalated materials with promising future applications in nanoporous electronic devices, where a high surface area coupled with fine-tuned electronic properties are desired.</div>

scholarly journals Oxidation of alkyl benzenes by a flavin photooxidation catalyst on nanostructured metal-oxide films

2017 ◽  
Vol 114 (35) ◽  
pp. 9279-9283 ◽  
Author(s):  
Prateek Dongare ◽  
Ian MacKenzie ◽  
Degao Wang ◽  
David A. Nicewicz ◽  
Thomas J. Meyer
Keyword(s):  
Metal Oxide ◽  
Surface Area ◽  
Aromatic Hydrocarbons ◽  
High Surface ◽  
High Surface Area ◽  
Oxide Films ◽  
Flavin Mononucleotide ◽  
Metal Oxide Films ◽  
Alkyl Benzenes ◽  
Nanostructured Metal

We describe here a surface-bound, oxide-based procedure for the photooxidation of a family of aromatic hydrocarbons by a phosphate-bearing flavin mononucleotide (FMN) photocatalyst on high surface area metal-oxide films.

A Green and Sustainable Approach for Acetalization of Benzaldehyde Using Tungstophosphoric Acid Loaded on Metal Oxide Catalysts

2019 ◽  
Vol 41 (5) ◽  
pp. 805-805
Author(s):  
Li Fanghao Li Fanghao ◽  
Li Chenjie Li Chenjie ◽  
Chen Junyi Chen Junyi ◽  
Wang Kuiwu Wang Kuiwu ◽  
Zhang Haijiang Zhang Haijiang ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Condensation Reaction ◽  
High Surface ◽  
High Surface Area ◽  
Synergetic Effect ◽  
Reaction Model ◽  
Oxide Catalysts ◽  
Tungstophosphoric Acid ◽  
Impregnation Method ◽  
Metal Oxide Catalysts

A series of tungstophosphoric acid (H3PW12O40; HPW) loaded on metal oxide catalysts, namely H3PW12O40/M (M= TiO2, CeO2, ZrO2) was prepared by initial wetting impregnation method and their catalytic performances were also investigated during the condensation reaction of benzaldehyde with glycol. Among them, the 20 wt% H3PW12O40/TiO2 catalyst demonstrated highly active with superior acetal yield (90.1 %) and excellent durability. The high activity of the catalyst derived from high surface area, ultra-strong Brand#248;nsted acidity and synergetic effect of Brand#248;nsted-Lewis acid. Response surface methodology (RSM) based on Box-Behnken design (BBD) was used to optimize the course of the condensation reaction of benzaldehyde with glycol, and the optimal benzaldehyde glycol acetal yield (93.4 %) could be obtained. The optimized yield and the experimental results are similar. Moreover, under optimal reaction conditions, the activation energy (Ea) of reaction could be obtained through the kinetic study of the irreversible parallel reaction model, and the Ea was 23.24 kJ/mol.

scholarly journals The Role of Surface Hydroxylation, Lattice Vacancies and Bond Covalency in the Electrochemical Oxidation of Water (OER) on Ni-Depleted Iridium Oxide Catalysts

2020 ◽  
Vol 234 (5) ◽  
pp. 787-812 ◽  
Author(s):  
Hong Nhan Nong ◽  
Hoang Phi Tran ◽  
Camillo Spöri ◽  
Malte Klingenhof ◽  
Lorenz Frevel ◽  
...  
Keyword(s):  
Metal Oxide ◽  
High Surface ◽  
High Surface Area ◽  
Oxide Shell ◽  
Mixed Metal Oxide ◽  
Support Materials ◽  
Oxide Support ◽  
Rich Alloy ◽  
Surface Hydroxylation

AbstractThe usage of iridium as an oxygen-evolution-reaction (OER) electrocatalyst requires very high atom efficiencies paired with high activity and stability. Our efforts during the past 6 years in the Priority Program 1613 funded by the Deutsche Forschungsgemeinschaft (DFG) were focused to mitigate the molecular origin of kinetic overpotentials of Ir-based OER catalysts and to design new materials to achieve that Ir-based catalysts are more atom and energy efficient, as well as stable. Approaches involved are: (1) use of bimetallic mixed metal oxide materials where Ir is combined with cheaper transition metals as starting materials, (2) use of dealloying concepts of nanometer sized core-shell particle with a thin noble metal oxide shell combined with a hollow or cheap transition metal-rich alloy core, and (3) use of corrosion-resistant high-surface-area oxide support materials. In this mini review, we have highlighted selected advances in our understanding of Ir–Ni bimetallic oxide electrocatalysts for the OER in acidic environments.

High surface area SiC(O)‐based ceramic by pyrolysis of poly (ethylene glycol) methacrylate‐modified polycarbosilane

2019 ◽  
Vol 102 (12) ◽  
pp. 7187-7197 ◽  
Author(s):  
Sarabjeet Kaur ◽  
Simon Fischer ◽  
Jens Falta ◽  
Kurosch Rezwan ◽  
Michaela Wilhelm
Keyword(s):  
Ethylene Glycol ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Poly Ethylene Glycol ◽  
Glycol Methacrylate ◽  
Poly Ethylene
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