Nanocasting of hierarchically porous Co3O4, Co, NiO, Ni, and Ag, monoliths: Impact of processing conditions on fidelity of replication

Sayler, Franchessa M.; Grano, Amy J.; Smått, Jan‐Henrik; Lindén, Mika; Bakker, Martin G.

doi:10.1016/j.micromeso.2013.10.011

Cited by 19 publications

(13 citation statements)

References 66 publications

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“…For the synthesis of porous solids, various different strategies have been established . Even though soft- and hard-templating approaches are the most widely used ones, both techniques still present inherent disadvantages. − In particular, the main critical step for both routes is template removal with the risk of collapse or deformation , of the entire nanostructure. Moreover, the soft-templating route usually requires the removal of templating agents by washing with organic solvents or thermal treatment, which is not sustainable and may lead to the formation of carbonaceous residues, respectively, , while usually producing amorphous materials. , The hard-templating issues are due to structural and compatibility restrictions between the rigid solid template and the precursor. , Additionally, hard-template removal is rather inconvenient: the procedure is usually quite time-consuming and requires several steps and the use of hazardous chemicals in order to completely dissolve the templating species …”

Section: Introductionmentioning

confidence: 99%

Reactive Hypersaline Route: One-Pot Synthesis of Porous Photoactive Nanocomposites

et al. 2017

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Herein, porous photoactive nanocomposites are prepared by a simple one-pot synthesis approach using a salt and aqueous media. Within this reactive hypersaline route, the salt not only serves in the structuring of the composite but also becomes an integral active part of it. Here, the addition of sodium thiocyanate to a titania precursor guides, on the one hand, the formation of needle-shaped nanoparticles and, on the other hand, forms yellow compound isoperthiocyanic acid, which is homogeneously incorporated into the porous nanocomposite. Compared to a pure titania reference, this material reveals a 7-fold-increased photodegradation rate of Rhodamine B as a model compound. This reveals the reactive hypersaline route to be a promising and facile synthesis route toward photoactive porous materials.

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Section: Introductionmentioning

confidence: 99%

Reactive Hypersaline Route: One-Pot Synthesis of Porous Photoactive Nanocomposites

et al. 2017

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“…Sayler et al reported a general nanocasting approach to synthesize Co 3 O 4 and NiO with hierarchically porous structures using a hierarchically porous silica as the hard template. 38 A hierarchically porous structure can also be achieved by adding potassium salts in the synthesis of MnO 2 , resulting in a tetramodal micro-meso-macroporous structure. 39 Another intriguing idea to create hierarchical porosity is to etch away portions of the nanopore walls.…”

Section: Metal Oxides With Hierarchicalmentioning

confidence: 99%

“…Recently, hierarchically porous metal oxides have attracted significant attention because they, as shown in the np-CuTi case, can possess distinctive properties such as high surface area, highly accessible pores, and enhanced mass transport capability. Sayler et al reported a general nanocasting approach to synthesize Co 3 O 4 and NiO with hierarchically porous structures using a hierarchically porous silica as the hard template . A hierarchically porous structure can also be achieved by adding potassium salts in the synthesis of MnO 2 , resulting in a tetramodal micro-meso-macroporous structure .…”

Section: Metal Oxides With Hierarchical Nanoporositymentioning

confidence: 99%

Synthesis of Nanoporous Metals, Oxides, Carbides, and Sulfides: Beyond Nanocasting

Luc

Jiao

2016

Acc. Chem. Res.

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Nanoporous metal-based solids are of particular interest because they combine a large quantity of surface metal sites, interconnected porous networks, and nanosized crystalline walls, thus exhibiting unique physical and chemical properties compared to other nanostructures and bulk counterparts. Among all of the synthetic approaches, nanocasting has proven to be a highly effective method for the syntheses of metal oxides with three-dimensionally ordered porous structures and crystalline walls. A typical procedure involves a thermal annealing process of a porous silica template filled with an inorganic precursor (often a metal nitrate salt), which converts the precursor into a desired phase within the silica pores. The final step is the selective removal of the silica template in either a strong base or a hydrofluoric acid solution. In the past decade, nanocasting has become a popular synthetic approach and has enabled the syntheses of a variety of nanoporous metal oxides. However, there is still a lack of synthetic methods to fabricate nanoporous materials beyond simple metal oxides. Therefore, the development of new synthetic strategies beyond nanocasting has become an important direction. This Account describes new progress in the preparation of novel nanoporous metal-based solids for heterogeneous catalysis. The discussion begins with a method called dealloying, an effective method to synthesize nanoporous metals. The starting material is a metallic alloy containing two or more elements followed by a selective chemical or electrochemical leaching process that removes one of the preferential elements, resulting in a highly porous structure. Nanoporous metals, such as Cu, Ag, and CuTi, exhibit remarkable electrocatalytic properties in carbon dioxide reduction, oxygen reduction, and hydrogen evolution reactions. In addition, the syntheses of metal oxides with hierarchical porous structures are also discussed. On the basis of the choice of hard template, nanoporous metal oxides with bimodal pore size distributions can be obtained. Combining nanocasting with chemical etching, a cobalt oxide with a hierarchical porous structure was synthesized, which possessed a surface area up to 250 m(2) g(-1), representing the highest surface area reported to date for nanoporous cobalt oxides. Lastly, this Account also covers the syntheses of nanoporous metal carbides and sulfides. The combination of in situ carburization and nanocasting enabled the syntheses of two ordered nanoporous metal carbides, Mo2C and W2C. For nanoporous metal sulfides, an "oxide-to-sulfide" synthetic strategy was proposed to address the large volume change issue of converting metal nitrate precursors to metal sulfide products in nanocasting. The successful syntheses of ordered nanoporous FeS2, CoS2, and NiS2 demonstrated the feasibility of the "oxide-to-sulfide" method. Concluding remarks include a summary of recent advances in the syntheses of nanoporous metal-based solids and a brief discussion of future opportunities in the hope of stimulating new inte...

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“…Hierarchically porous monoliths, termed ‘HP monoliths’ hereafter, with 3D interconnected macropores and open nanopores have been studied for various applications, such as separation [ 1–4 ], electrochemistry [ 5–9 ], adsorbence [ 10–12 ], catalysis [ 13 ] and as support materials for catalyst/enzyme [ 14 , 15 ]. One of the synthetic strategies to prepare HP monoliths is spatial arrest of the transient state in the process of spinodal decomposition by gelation [ 16 ], as illustrated in Scheme 1 .…”

Section: Introductionmentioning

confidence: 99%

Hierarchically porous monoliths based on low-valence transition metal (Cu, Co, Mn) oxides: gelation and phase separation

Kanamori

Nakanishi

2020

National Science Review

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Hierarchically porous monoliths based on copper (Cu), cobalt (Co), and manganese (Mn) oxides with three-dimensionally (3D) interconnected macropores and open nanopores have been prepared using metal bromides as precursors via sol–gel process accompanied by phase separation. The difficulty of gelation for low-valence metal cation was overcome by introducing a highly electronegative Br atom nearby the metal atom to control the rates of hydrolysis and polycondensation. The 3D interconnected macropores were obtained using appropriate polymers to induce the phase separation. The domain sizes of macropores and skeletons can be controlled by reaction parameters such as concentration and/or average molecular weight of polymers, and the amount of hydrochloric acid. The crystalline metal oxide monoliths with their 3D interconnected macroporous structure preserved were obtained after the heat treatment in air.

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Nanocasting of hierarchically porous Co3O4, Co, NiO, Ni, and Ag, monoliths: Impact of processing conditions on fidelity of replication

Cited by 19 publications

References 66 publications

Reactive Hypersaline Route: One-Pot Synthesis of Porous Photoactive Nanocomposites

Reactive Hypersaline Route: One-Pot Synthesis of Porous Photoactive Nanocomposites

Synthesis of Nanoporous Metals, Oxides, Carbides, and Sulfides: Beyond Nanocasting

Hierarchically porous monoliths based on low-valence transition metal (Cu, Co, Mn) oxides: gelation and phase separation

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