Microstructure and Catalytic Activity of Hierarchical Porous HEA Catalysts Fabricated by 3D Printing/Chemical Dealloying

High-entropy alloys (HEAs) exhibit excellent catalytic activity owing to their unique structure and chemical properties. The construction of hierarchical porous HEA catalysts via laser powder bed fusion (LPBF, a typical 3D printing technology) and dealloying techniques opens new avenues for boosting catalytic performance. This study reports the fabrication of a hierarchical porous FeCoNiCuAl HEA catalyst through a two-step strategy: LPBF and subsequent dealloying. The macroscopic triply periodic minimal surface (TPMS) structure of the HEA catalyst was constructed through LPBF, followed by dealloying to create a nanoporous structure on the catalyst surface. The hierarchical porous FeCoNiCuAl HEA catalyst exhibited a catalytic activity 4.33 times higher than that of the pristine, non-porous FeCoNiCuAl HEA (HEA-0). Furthermore, the catalyst maintained nearly 100% degradation efficiency for Acid Red G (ARG) after 20 consecutive catalytic cycles, demonstrating exceptional stability. This stepwise strategy for constructing hierarchical porous structures not only accelerates mass transfer via the macroporous framework but also significantly increases the density of accessible active sites through the nanoporous surface, thereby synergistically enhancing the catalytic activity of HEAs. This work provides a novel and scalable approach for developing high-performance porous HEA catalysts for wastewater treatment.