Towards mesoporous Keggin-type polyoxometalates – systematic study on organic template removal

Abstract

Here, we present systematic studies on the removal of the polymer template from inverse hexagonally ordered poly(butadiene-block-2-dimethylaminoethyl methacrylate)-phosphomolybdic acid (H 3 PMo 12 O 40 ) nanocomposites. Highly ordered mesophases are obtained via an evaporation-induced self-assembly process. Different techniques are used to remove the organic template: direct calcination in air, a two-step heat treatment ((1) argon atmosphere and (2) oxidative atmosphere), and a combination of heat and plasma treatment. Our studies show that direct calcination in air and two-step heat treatment lead to a collapse of mesostructure before complete carbon removal is accomplished. In contrast, plasma etching of heat treated ultra-microtomed samples results in hexagonally ordered porous nanofilms.

Selective Template Removal by Thermal Depolymerization to Obtain Mesostructured Molybdenum Oxycarbide

“…The removal of the residual carbon inside the pores proved impossible leading to partial blockage of the inner surface area. [8] To obtain carbon-free mesostructured transition metal carbides the carbon content needs to be reduced prior to the carburization step without loss of the mesostructure.…”

Selective conversion of starch to glucose using carbon based solid acid catalyst

“…Even in the supported system, similar pattern was noticed with a spin-orbit doublet but at a slightly lower BE values. These slight shifts could be attributed to the metal (W) e support (activated carbon) interaction [33,34].…”

Festkörperchemie 2013

“…Insbesondere weisen Heteropolyoxometallate des Keggin‐Typs eine definierte Größe und negative Ladung auf. Diese Ladung machten sich Lunkenbein et al aus der Gruppe Breu zu Nutze, um hexagonal geordnete Mesophasen über Coloumb‐Wechselwirkungen zwischen einem amphiphilen ionogenen Diblockcopolymer und Molybdophosphorsäure aufzubauen 31. Für die volle Funktionalität solcher mesostrukturierter Materialien ist allerdings die kohlenstoffhaltige Matrix zu entfernen.…”