Combined electrochemical, atomic scale-DFT and MD simulation of Nickel based metal organic framework (Ni-MOF) as corrosion inhibitor for X65 pipeline steel in CO2- saturated brine

Ni-based metal organic framework (Ni-MOF) was synthesized using nickel nitrate hexahydrate as a central metal cation and 2 methyl imidazole as an organic linker. The synthesis was done under room temperature via chemical method. The MOF precipitate was characterized and tested for its efficacy in mitigation of CO2 corrosion on X65 pipeline steel. The synergistic effect of Ni-MOF was appraised using combined electrochemical and surface characterizations techniques. Maximum inhibition efficiency of 94 % was achieved at Ni-MOF_0.1 wt %. The trend of the experimental data indicates that Ni-MOF acts as a mixed-type inhibitor. Also, the presence of the organic ligand not only expedites the coordination with the metal cation, but enhanced the framework activity by forming a barrier film on the steel surface, which accounts for the better inhibitive effect of Ni-MOF as evidenced through surface analysis and DFT/MD studies. Thus, the overall lowering of the corrosion rate is as a result of the formation of a stable hybrid protective film on the X65 steel surface.