Designing multifunctional basalt-CeO₂@C₃N₄/epoxy novolac composite coating with outstanding corrosion resistance and CO2 gas barrier properties

The greenhouse effect caused by CO2 emissions is becoming more and more serious, and the carbon capture, utilization and storage (CCUS) is a feasible strategy to reduce emissions. However, the corrosion problem brought by CCUS is unprecedentedly serious. In this paper, we present a composite epoxy novolac (EN) system for resisting corrosion of metals in CCUS environments. In this system, nanorod CeO2 and nanosheet C3N4 are simultaneously grown on the surface of the micron sheet basalt (Bt), which are used as effective additives to improve the corrosion resistance and CO2 gas barrier properties of EN. Only with 3 % of nanoparticles addition, a significant reduction of the gas diffusion of composite film to dry CO2 has been observed, up to 5.88 x 10(-12) m(2)/s. This is associated with the synergistic enhancement of the physical shielding effect by the nano and micron sheets. Additionally, we found that adsorption of oxygen vacancy of CeO2 material with CO2 enhances the stability of corrosion resistance. Therefore, the |Z|(0.01 Hz) of the Bt-CeO2@C3N4/EN coating is above 10(6) Omega cm(2) higher than that of the EN coating after 25 days of immersion in a 3.0 MPa CO2 aqueous solution at 70 degrees C. Overall, the anti-corrosion coating system combines long-lasting water resistance and low CO2 gas transmission in harsh corrosive environments, and thus has a high potential for CCUS applications.