The exploration of novel electrocatalysts for CO 2 reduction is necessary to overcome global warming and the depletion of fossil fuels. In the current study, the electrocatalytic CO 2 reduction of [Re(CO) 3 Cl( N - N )], where N - N represents 3-(2-pyridyl)-1,2,4-triazole (Hpy), 3-(pyridin-2-yl)-5-phenyl-l,2,4-triazole (Hph), and 2,2′-bipyridine-4,4′ dicarboxylic acidic (bpy-COOH) ligands, was investigated. In CO 2 -saturated electrolytes, cyclic voltammograms showed an enhancement of the current at the second reduction wave for all complexes. In the presence of triethanolamine (TEOA), the currents of Re(Hpy), Re(Hph), and Re(bpy-COOH) enhanced significantly by approximately 4-, 2-, and 5-fold at peak potentials of −1.60, −150, and −1.69 V Ag/Ag+ , respectively (in comparison to without TEOA). The reduction potential of Re(Hph) was less negative than those of Re(Hpy) and Re(COOH), which was suggested to cause its least efficiency for CO 2 reduction. Chronoamperometry measurements showed the stability of the cathodic current at the second reduction wave for at least 300 s, and Re(COOH) was the most stable in the CO 2 -catalyzed reduction. The appearance and disappearance of the absorption band in the UV/vis spectra indicated the reaction of the catalyst with molecular CO 2 and its conversion to new species, which were proposed to be Re- DMF + and Re- TEOA and were supposed to react with CO 2 molecules. The CO 2 molecules were claimed to be captured and inserted into the oxygen bond of Re- TEOA , resulting in the enhancement of the CO 2 reduction efficiency. The results indicate a new way of using these complexes in electrocatalytic CO 2 reduction.

The self-formation of a porous organic thin-film via corrosion inhibitor supports wide applications of carbon steel in industry. Unfortunately, serious damages could be concentrated to the pinhole and/or pore locations in the porous organic film, resulting in the localized corrosion even when an optimal concentration of organic corrosion inhibitors is used. In this work, SnO2 nanoparticles are used for producing the more robust barrier layer via the self-migration of nanoparticles, resulting in a higher corrosion resistance, smooth and uniform protective layer, as well as the existence of SnO2 in the protective layer that could directly affect the high inhibition performance. Therefore, the work suggests a new way to make a more robust thin film that could extend the use of organic corrosion inhibitors.