Hierarchically porous gold with Russian matryoshka doll-like three-level structure for fast charge transport and high specific surface area

Hierarchically porous skeleton possesses fascinating ion diffusion shortcuts and a unique intertwined metallic network, as well as abundant electroactive sites. This provides an intriguing structural condition for fast energy conversion or charge transfer process. Although two-level nested-network nanostructure has been extensively investigated, the preparation strategy for a perfect self-similar three-level porous structure, like Russian matryoshka doll (RMD), is still to be developed. Herein, we present a novel method that combines electrochemical dealloying and chemical dealloying to fabricate RMD-like three-level hierarchical np-Au (RMD-N 3 PG). In this structure, the ligament sizes are categorized into three levels: approximately 500 ​nm, 100 ​nm, and 20 ​nm. The superiority of the RMD-like three-level hierarchical structure is demonstrated in charge transport kinetics, benchmarked against one-level and two-level NPG (NPG and N 2 PG) scenarios. Additionally, structural hierarchy may enhance the exposure of active sites by reducing nonessential intercontact or overlap of ligaments, thereby improving the surface utilization of small pores, increasing the electrochemical active surface area. This method provides a valuable and practical reference for the preparation of multi-level structures with both fast mass transport and high specific surface area.