A surface molecular assembly-based composite inhibitor for mitigating corrosion in dynamic supercritical CO2 aqueous environment

Supercritical CO2 (sCO2) corrosion is a persistent challenge in carbon capture, utilization, and storage (CCUS) that requires effective inhibition strategies. We present a systematic study using experimentation and modeling to investigate the inhibition behavior of a composite formulation containing Sodium Molybdate (SM), Triethanolamine Borate (TB), and L-Cysteine (LC) on X80 steel. Our in situ electrochemical studies confirm the superior performance of this ternary system, achieving a composite inhibition efficiency of over 99.86%. Surface profilometry measurements showed a roughness value as low as 33.51μm, indicating enhanced corrosion resistance and uniformity. Atomistic simulations provided mechanistic insights, revealing that LC coordinates SM and TB through favorable S-mediated interactions, optimizing the interfacial ligand network. Chemical bonding analysis indicated that this designed interface effectively suppresses corrosion through cooperative interactions, exceeding the performance of individual inhibitors. Overall, the synergistic effects of the optimized multicomponent system surpassed the efficacy expected from simply combining the individual components.