L-cysteine reduced/functionalized graphene oxide application as a smart/control release nanocarrier of sustainable cerium ions for epoxy coating anti-corrosion properties improvement

摘要

One of the main limitations for large scale mass production of reduced graphene oxide is the application of some toxic and hazardous reducing agents such as hydrazine and borohydride. In this study, the effectiveness of the LCys (HSCH2CH(NH2)CO2H) molecules, as a green amino acid in the GO reduction, as well as its active corrosion inhibition capacity were explored. The L-Cys/GO nanosheets were then modified by trivalent-cerium ions to obtain a nanocarrier with excellent controlled release activity. The electrochemical impedance spectroscopy (EIS) and polarization tests were used to measure the smart corrosion inhibition activity of the cerium modified L-Cys/GO nanocarrier in the saline solution and epoxy coating. The results showed that the cerium ions adsorption on the L-Cys/GO nanosheets obeyed a Langmuir isotherm model. The L-Cys/GO sample showed cerium ions adsorption capacity about 66% higher than the unmodified GO nanosheets. Furthermore, the EIS tests results revealed that in the presence of cerium modified L-Cys/GO nanocarriers the improvement in the corrosion resistance of bare steel in the solution phase and coated sample was about 7.5 times (after 24 h) and 950 times (after 40 days) higher than the blank saline solution and the pure epoxy sample, respectively.