Dimensionally Stable Anodes (DSA®) are used for large-scale production of e.g. chlorine and chlorate, which are energy-consuming processes. A typical anode consists of a Ti substrate coated with Ti0.7Ru0.3O2. It is widely believed, that the success of the DSA® results from the large electrocatalytic area due to the cracked mud structure [1]. This micrometer sized cracked structure is well known, but on the nanoscale, for example, on the top of the plaquettes, the number of studies are limited [2].
To improve the DSA® electrodes an obvious way is to increase the active area and thus decrease the energy need, but normally this also means a more porous oxide with a shorter lifetime. If the surface topology could be controlled at the nanoscale it might be possible to both increase the area and keep the coating stable over time.
We plan to do nanolithography of the electrodes, which in industrial applications can have dimensions of the order of square meters. To achieve this we will use nanoimprint methods [3]. However, first a better understanding the nanostructure of these electrodes is needed.
Here, we report on AFM and TEM characterization of the DSA®. AFM imaging on top of the plaquettes shows a rough surface on the nanoscale. TEM images shows that this is not just a surface phenomenon, but the whole coating seems to be built up of 20-50 nm sized grains. In addition to characterization we will discuss our approach for nanoimprinting of these electrodes.
[1] S. Trasatti, Electrocatalysis: understanding the success of DSA®, Electrochim. Acta 45 (2000) 2377
[2] C.E. Vallet, Comparison of scanning probe microscopies with RBS and SEM/EDX for analysis of RuO2, TiO2 composites, Appl. Phys. A. 65 (1997) 387
[3] B. Heidari, I. Maximov, and L. Montelius, Nanoimprint lithography at the 6 in. wafer scale, J. Vac. Sci. Techn. B 18 (2000) 3557
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