Effect of oxygen based functional groups on the nucleation of TiO2 by atomic layer deposition: A theoretical and experimental study

The chemical affinity of functional nanostructured materials based on nanoporous carbon selectively functionalized, and titanium oxide is presented. Nanoporous carbon was modified using the diazonium chemistry to graft different oxygen functional groups (CM-cp-R, where R = OH, CHO or COOH) from different aniline precursors. Nanostructured materials were fabricated by atomic layer deposition (ALD), using (Tetrakis(dimethylamino)titanium) and water as precursors, and CM-cp-R as substrates. In the ALD process, the chemical environment is a key factor in the first stages of thin-film growth. To analyze the affinity of functional groups on the TiO2 nucleation, and their effect on their electrochemical properties, the CM-cp-R were exposed to 20 ALD cycles. The chemical modification of CM-cp-R and nucleation of TiO2 on CM-cp-R was analyzed by spectroscopic and microscopic techniques. These analysis shows a higher affinity of TiO2 on CM-phi-COOH, as well as improved capacitance performance in high rate electrochemical test. The composite systems were studied with the aid of Density Functional Theory calculations. The nucleation with the oxide was modeled with a TiO2 reduced model. The electronic structure properties showed a more effective TiO2 grafting with cp-COOH functional group confirming experimental observations, in which an electrostatic attraction of the van der Waals type was involved.