Oxidative detemplating

Oxidization Detemplating with Ozone under Mild Conditions (Oxidation Detemplating)... 

It is evident that dedicated studies are required for each structure to optimize the template oxidation protocol. Many structures, in particular nonsiliceous, are thermally very sensitive [14, 15]. Calcination can result in a complete breakdown due to hydrolysis, redox processes, and phase transformations. The removal of templates in those systems is critical, making the development of mild detemplation techniques necessary [16]. 

We discuss here a combined process including detemplation and Fe incorporation by ion-exchange in the zeolite framework [147]. To achieve this, oxidants to decompose the organic template and Fe-cations for exchange are needed. Both requirements are in harmony with Fenton chemistry. The OH radicals can oxidize the template and the Fe-cations be exchanged simultaneously. 

Recent reports describe more sophisticated detemplation methods. However, they are limited to mesoporous materials for the reasons described before. We show how Fenton chemistry can fulfill various missing challenges (i) it provides a powerful oxidation capacity at low(er) temperatures and (ii) it can work for microporous compounds as well. 

The approach consists of a liquid-phase oxidation using OH Fenton radicals from H2O2 for detemplation [148-150]. The radicals oxidize the organic template into CO2 and H2O while the porosity of the material is developed. The proof-of-principle of this concept is discussed for two case studies. 

I 6 Oxidation Tools in the Synthesis of Catalysts and Related Functional Materials Table 6.1 Detemplation approaches of micro- and mesoporous materials. 

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