Nucleation and growth of manganese oxides on metallic surfaces as a tool to prepare metallic monoliths

Abstract

The use of austenitic stainless steel (AISI 304) as metallic substrate for catalytic devices is explored in this work as well as an alternative procedure to the washcoating of the active phase. Catalyst deposition on austenitic stainless steel takes advantage of the manganese concentration of this alloy by direct growing of the new catalytic phase on the monolith surface during the synthesis. Manganese oxide (OMS) is chosen as active phase and VOC abatement by total oxidation as catalytic test. It is possible to coat metallic monoliths by growing the catalytic phase, manganese oxide (OMS), in situ during the reflux synthesis of cryptomelane. This preparation strategy needs a proper metal surface modification but is possible to deposit a large amount of catalyst in a very adherent form. The metallic coating shows similar adherences to those found using Fecralloy substrates even thought, in the case of the monolith prepared by repeated washcoating on AISI 304, new phases seem to be produced showing quite higher activity in total oxidation of ethyl acetate.