Microstructure Engineered Bulk Nanoporous Copper With Tunable Plasmonic Properties for Surface‐Enhanced Raman Spectroscopy

ABSTRACT This study presents a kinetically guided approach for fabricating robust, bulk nanoporous copper (NPC) with tunable plasmonic properties. A free‐corrosion dealloying process was used to produce uniform, three‐dimensional bicontinuous structures by systematically varying the initial Ti–Cu alloy composition and HF etchant concentration. We demonstrate that the precursor's phase constitution—single‐phase TiCu versus dual‐phase TiCu + TiCu 2 —combined with the HF concentration governs, dealloying kinetics and final pore architecture. Electrochemical Tafel analysis confirms that the dual‐phase precursor exhibits accelerated dissolution kinetics, enabling precise pore size tuning from ∼50 to ∼200 nm. An optimal macroscopically crack‐free, interpenetrating ligament‐channel network with ∼150 nm pores is achieved under specific kinetic conditions. When employed as substrates for surface‐enhanced Raman spectroscopy (SERS), these NPC exhibit plasmonic properties intrinsically linked to microstructure. Maximum SERS enhancement for Rhodamine 6G occurs at ∼150 nm pore size, reflecting an optimal balance between electromagnetic field enhancement and plasmonic damping associated with residual titanium. This work provides a comprehensive investigation of kinetic effects during Ti–Cu dealloying and demonstrates how controlled processing–microstructure relationships can be utilized to engineer macroscopically crack‐free bulk nanoporous copper for SERS applications.