Template assisted preparation of high surface area macroporous supports with uniform and tunable nanocrystal loadings

Abstract

The incorporation of catalytic nanocrystals into macroporous support materials has been very attractive due to their increased catalyst mass activity. This increase in catalytic efficiency is attributed in part to the increased surface area to volume ratio of the catalysts and the use of complementary support materials that can enhance their catalytic activity and stability. A uniform and tunable coating of nanocrystals on porous matrices can be difficult to achieve with some techniques such as electrodeposition. More sophisticated techniques for preparing uniform nanocrystal coatings include atomic layer deposition, but it can be difficult to reproduce these processes at commercial scales required for preparing catalyst materials. In this study, catalytic nanocrystals supported on three dimensional (3D) porous structures were prepared. The demonstrated technique utilized scalable approaches for achieving a uniform surface coverage of catalysts through the use of polymeric sacrificial templates. This template assisted technique was demonstrated with a good control over the surface coverage of catalysts, support material composition, and porosities of the support material. A series of regular porous supports were each prepared with a uniform coating of nanocrystals, such as NaYF4 nanocrystals supported by a porous 3D lattice of Ti1-xSixO2, Pt nanocrystals on a 3D porous support of TiO2, Pd nanocrystals on Ni nanobowls, and Pt nanocrystals on 3D assemblies of Au/TiO2 nanobowls. The template assisted preparation of high surface area macroporous supports could be further utilized for optimizing the use of catalytic materials in chemical, electrochemical, and photochemical reactions through increasing their catalytic efficiency and stability.

Electrochemically Aged Ni Electrodes Supporting NiFe2O4Nanoparticles for the Oxygen Evolution Reaction

“…Sulfate functionalized PS spheres with a hydrodynamic diameter of 500 nm (Polysciences, Inc., Lot No. 656986) were purified according to previously established methods . Anhydrous ethyl alcohol (EtOH, Commercial Alcohols, CAS No.…”

“…These templates also provided a simple means to prepare a regular morphology for tracking changes that could result from prolonged electrochemical aging. A monolayer of the NiFe 2 O 4 -coated PS spheres was self-assembled at an air–water interface by adapting previously reported procedures. , In brief, these spherical particles, suspended in 1-butanol, were drop-cast onto an air–liquid interface. The liquid consisted of DI water, which was heated to ∼60 °C to slowly evaporate the 1-butanol during the drop-cast procedure.…”

“…The formation of aggregates in particle-based inks can result in a reduction of the electrochemically active surface area ( A ecsa ) as well as a loss of electron transfer pathways. Previous work has established the use of template-assisted methods to more effectively position and utilize NPs on the surfaces of conductive supports. , These template-assisted approaches can be used to uniformly position NP-based electrocatalysts on conductive, structured support matrices. Immobilization and partial embedding of the NP electrocatalysts at the surfaces of conductive supports reduce the potential for NP aggregation.…”

Microwave assisted solvothermal synthesis of quasi cubic F doped TiO2 nanostructures and its performance as dye sensitized solar cell photoanode

“…Using polymeric materials as dopant materials serves dual purpose it acts as dopant, and at the same time, they can also improve the porosity of the material and the polymers can be easily removed from the final product. 33 Among the different chemical methods used for the synthesis of nanomaterials, microwave assisted technique is one of the significant method in which the reaction time can be brought down to a considerable level. In the microwave technique, the reactants, which are active to microwaves,gain instant energy in the form of heat on the exposure to microwaves.…”

“…Among them, PVDF has been utilized previously as fluorine dopant in variety of materials and applications. Using polymeric materials as dopant materials serves dual purpose it acts as dopant, and at the same time, they can also improve the porosity of the material and the polymers can be easily removed from the final product 33 …”