Self-supported carbon membranes

For dry reforming, carbon formation is very likely, especially when carried out in a membrane reactor [24]. For this application noble metals are used, which are intrinsically less prone to carbon formation because, unlike nickel, they do not dissolve carbon. Irusta et al. [24] have shown above-equilibrium methane conversion in a reactor equipped with a self-supported Pd-Ag tube. Small amounts of coke were formed on their Rh/La203/Si02 catalyst, but this is reported not to have any effect on activity. 

Recently activated carbons such as activated carbon fibers (ACFs) and superhigh surface area carbons have been developed. New activated carbons have more uniform micropore size distribution and greater surface area than traditional activated carbons. The carbon membranes for gas separation have been also developed lately[8]. The activation of the polyamide film leads to self-supported activated carbon film whose surface area is larger than 1100 m /g [9]. Thus various kinds of carbon adsorbents have been developed to find new applications. Scientific studies on activated carbon have been increasing according to development of these new carbon adsorbents with a special relevance to energy and environmental demands. In particular, controll of an adsorptive ability of activated carbon is requisite for new application. Consequently, basic principles for control of the micropore filling mechanism of activated carbons are shown here. 

Many membrane modules have been proposed by researchers. The most challenging task that must be considered during the fabrication of such modules is the poor mechanical stability of carbon membranes. This is more cracial in hollow fiber carbon membranes since they are self-supporting. More effort is now needed to develop a suitable module configuration and module design to accommodate carbon fibers. 

Zeolite membranes can also be prepared by the LBL self-assembly technique by using other inert supports, such as gold and carbon, instead of polystyrene beads. This technique for film preparation has several advantages. First, it is the first example of... 

Chen et al recently reported the fabrication and characterization of a high power self-breathing PEMFC with optimally designed wet KOH etched flow-fields and electrodes [49]. Ni/Cu/Au layers are used for current collecting, the 1.5 /im-thick in-between layer instead of a thick Au layer allowing to reduce the fabrication cost. The MEA is composed of a classical Nafion -1135 membrane with Pt-alloy sprayed carbon paper on both sides. The two silicon electrodes are sandwiched and pressed at RT with the MEA, and then sealed with epoxy. A base-chip formed by drilled Pyrex glass anodically bonded with KOH eched silicon acted both as H2 inlet/outlet manifolds and as a support for a... 

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