Encapsulated High‐Entropy‐Alloy Nanoparticles within Graphitic Shell for Improved Long‐Term Prevention of Microbiologically Influenced Corrosion

Abstract Microbiologically influenced corrosion (MIC), a trillion‐dollar global issue, is driven by anaerobic biofilms that accelerate metal oxidation. Current MIC inhibition (MICI) strategies rely on antibiofilm materials and scrubbing aimed at biofilm removal but suffer from poor durability and limited mechanistic insight. Here, FeNiTiCrMnCu x high‐entropy alloy nanoparticles encapsulated within graphitic shells (HEA@C‐NPs) are presented as an efficient and durable MICI approach. The graphitic shell effectively prevents HEA@C‐NPs dissolution in corrosive environments, thereby enhancing structural stability and controlled copper ion release, thus significantly improving the durability and efficiency of MICI. Leveraging the synergistic effects of enzyme‐like activity, controlled copper ion release, and localized thermal disruption, 400 ppm (w/w) HEA@C‐NPs generate reactive oxygen species, leading to lactate and sulfate metabolism suppression and biofilm eradication in both artificial seawater and ATCC 1249 culture medium, achieving 99.99% efficiency in inhibiting planktonic Desulfovibrio vulgaris Hildenborough growth. In particular, the optimized FeNiTiCrMnCu 2 @C HEA‐NPs achieved 95% MICI efficiency against MIC of the sulfate reducing bacterium on Q235 carbon steel after 7 days, with sustained inhibition for at least 28 days in a full nutrient medium. This work pioneers a transformative strategy for designing new antibiofilm agents with exceptional sustainability and various potential industrial applications.