Titanium dioxide has been of high interest because of its UV-light absorbing properties and its ability to produce electron-hole pairs that are capable in catalyzing surface reactions. The discovery of the photocatalytic properties of TiO2 was first reported by Akira Fujishima in 1967. Since then, TiO2 nanomaterials have attracted tremendous interest for self-cleaning, energy harvesting, antimicrobial, and pollution mitigation applications. Research in semiconductor photocatalysis has recently included nanoparticles and nanostructured materials that possess the advantages of a robust material while retaining the unique properties of nanoscale particles.

The Pulsed-Pressure Metalorganic Chemical Vapor Deposition (pp-MOCVD) process has previously been studied for preparing antimicrobial nanostructured TiO2 coatings on 3D surfaces for healthcare facilities. The pp-MOCVD process is a single step deposition technique that produces conformal coatings of TiO2 on microscale features and on glass and stainless-steel substrates. The TiO2 coatings exhibit enhanced photocatalytic activity (PCA) under low energy visible light compared to the conventional TiO2 materials. Scanning electron microscopic (SEM) investigations revealed that the more active TiO2 thin films exhibit a rarely observed morphology of TiO2. Figure 1 shows the unique morphology of the TiO2-C coatings prepared by pp- MOCVD.

Figure 1 (a) Plan-view image & (b) cross-sectional view of a TiO2-C coating prepared via pp-MOCVD

X-ray diffraction studies (Figure 2 a) showed that the coatings consist of anatase and rutile phases of TiO2. The results showed that the columnar nanostructured TiO2 coatings are composed of highly textured anatase and polycrystalline-rutile. The characterization of the coatings showed that the films were composed of TiO2 with co- deposited carbon (Figure 2 b). Early results showed that the visible light active TiO2 coatings exhibit high-grade durability, and enhanced water splitting efficiency.