Electrochemical microreactors methods

Several methods for the incorporation of catalysts into microreactors exist, which differ in the phase-contacting principle. The easiest way is to fill in the catalyst and create a packed-bed microreactor. If catalytic bed or catalytic wall microreactors are used, several techniques for catalyst deposition are possible. These techniques are divided into the following parts. For catalysts based on oxide supports, pretreatment of the substrate by anodic or thermal oxidation [93, 94] and chemical treatment is necessary. Subsequently, coating methods based on a Uquid phase such as a suspension, sol-gel [95], hybrid techniques between suspension and sol-gel [96], impregnation and electrochemical deposition methods can be used for catalyst deposition [97], in addition to chemical or physical vapor deposition [98] and flame spray deposition techniques [99]. A further method is the synthesis of zeoUtes on microstructures [100, 101]. Catalysts based on a carbon support can be deposited either on ceramic or on metallic surfaces, whereas carbon supports on metals have been little investigated so far [102]. 

Nowadays, this method is extended to other metals such as Ti [187], Zr [188], Hf [189], and Nb [190] as well. In particular, the TiOj-based nanotubes are of special interest because of their specific potential use in optical, electrochemical, and catalytic applications [191]. The AAO has been used to functionalize and modify the walls of a microreactor and use the resulting porous system as catalyst support in ammonia reforming [192]. 

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