The high resolution characterization of nanoporous gold (NPG), a material with promising functional capabilities, facilitates better understanding of its structure-property relationships. An improved characterization of NPG by atom probe tomography (APT) was recently reported, using Cu electroplating to fill the pores [1]. Atomic scale analysis of nanoligaments showed the expected core-shell structure in high detail (Figure 1), confirming and extending previous findings using other characterization methods [2].

Further to those findings, finer, more complex nanoporous materials, formed by dealloying of AgAuPt alloys, have been studied by APT as well as STEM tomography, demonstrating an ever clearer 3D picture of the structure. As the extent of aberrations found in the data is directly related to the relative evaporation fields of the metals in the sample [3], further improvement of this technique prompts the search for alternative metallic fillers.

Figure 1- (a) Atom map of a single nanoligament in NPG formed by dealloying of Ag₇₇Au₂₃, (b) Chemical profiling across a single ligament.

References

[1] Ayman A. El-Zoka., Doug D. Perovic, Roger C. Newman, and Brian Langelier. "High Resolution Studies of Dealloyed Layers." In Meeting Abstracts, The Electrochemical Society, vol. 12, pp. 1259-1259, 2016.

[2] T. Fujita, P. Guan, K. McKenna, X. Lang, A. Hirata, L. Zhang, T. Tokunaga, S. Arai, Y. Yamamoto, N. Tanaka, Y. Ishikawa, N. Asao, Y. Yamamoto, J. Erlebacher and M. Chen, "Atomic origins of the high catalytic activity of nanoporous gold," Nature Materials, vol. 11, pp. 775-780, 2012.

[3] T.T Tsong, “Field ion formation,” Surf. Sci., vol. 70, pp. 211-233, 1978.