Master assignment: Rational design of conductive porous inorganic hollow fibers
Inorganic porous hollow fibers are used for a long time for their outstanding chemical, thermal and mechanical properties. Metallic hollow fibers are recently developed, but often lack the chemical and mechanical properties. Within our group we recently developed a method to coat a metallic layer onto an inorganic hollow fiber. These inorganic/metallic fibers can be used for a vast range of applications, for example as electrode/gas diffuser in electrochemical processes.
Using electroless plating, we are able to deposit layers of nickel or copper onto an aluminum oxide support, enhancing the fibers electrical conductivity. In this process, a fiber is submersed in a complexed metal solution and in the presence of a strong reducing agent, such as formaldehyde. The subsequent electrochemical reduction results in the growth of a small, thin metal layer which is impermeable.
In this assignment, the student will investigate if it is possible to deposit a porous metal layer on the outside, in such a way that there remains a percolating pathway that allows ion transport. One possibility would be permeating gas through the fiber during the deposition of the metal layer, resulting in open pores.
Further, an optimization study in terms of coating parameters (time, temperature, plating bath composition), coating solution (other metals) or processing conditions (gas pressure, transport modeling). The exact details of the assignment can be tailored based on the students own interests.