Loading and release mechanisms of MOF-5 @ BTA-X (X =-CH3/-NH2/-CO (CH2)6CH3): Experimental and theoretical investigations

A series of MOF-5 @BTA-X (X =-CH3/-NH2/-CO(CH2)6CH3) anticorrosion composites was fabricated through loading benzotriazole derivatives in a metal-organic framework (i.e., MOF-5). Their crystal structures and morphologies were characterized by single-crystal X-ray diffraction analysis, Fourier transform infrared spec-troscopy, and transmission electron microscopy. The loading-releasing mechanisms between MOF-5 and BTA derivatives were revealed by experiments and theoretical calculations. Their anticorrosion performance for copper was also evaluated by electrochemical impedance spectroscopy and potentiodynamic polarization in 0.5 M NaCl. The corrosion product was analyzed via scanning electron microscopy and X-ray photoelectron spec-troscopy. The results indicated that the loading capacities followed the order of MOF-5 @BTA-NH2 > MOF-5 @BTA-CH3 > MOF-5 @BTA-CO(CH2)6CH3. The release rates followed the order of MOF-5 @BTA-NH2 < MOF-5 @BTA-CH3 < MOF-5 @BTA-CO(CH2)6CH3. Furthermore, the results of theoretical calculations indicated that the differences in loading capacities depended on the polarity of the functional group. Meanwhile, the strong binding force decreased the release rate.