Porous anodic alumina optimized as a catalyst support for microreactors

This paper describes the optimization of process conditions for making porous anodic alumina as a catalyst support in monolithic microreactors. The basic process involves direct current anodization of 1100 alloy aluminum in oxalic acid. Electrolyte concentration, temperature, and anodization potential are optimized with respect to oxidation efficiency and pore density via a Box–Behnken experimental design to the values of 0.6 M, 18 °C, and 30 V, respectively. The effects of subsequent hydrothermal–thermal treatment on the surface area enhancement and surface morphology of the porous oxide are also investigated and optimized. The resulting films are employed in the fabrication of active catalytic aluminum–alumina microreactors for the decomposition of ammonia to hydrogen and nitrogen.