The growth of cases of nosocomial infections is an urgent issue in health care facilities. Reducing cross-contamination from high-frequency touch surfaces is a key area of interest. Robust TiO₂ coatings on touch surfaces could reduce pathogen viability if the material could be modified to increase photocatalytic activity (PCA) under visible light. Research has focused on increasing the bandgap by use of dopants and rutile-anatase heterojunctions, using nanoparticles to increase active surface area, and sensitizing TiO₂ with carbon. We have previously reported 11 μm thickness nanostructured anatase and rutile mixed phase TiO₂ and carbon composite coatings (NsARC) which are antimicrobial under visible light. Here we investigate the role of the co-deposited carbon in the antibacterial performance. Coatings of 4.0–6.0 μm thicknesses nanostructured anatase were deposited by pulsed-pressure metalorganic chemical vapor deposition (pp-MOCVD) on stainless steel and glass substrates, and one set was heat-treated to remove the co-deposited amorphous carbon. Morphology, phase and adhesion were not affected by the short heat treatment at 500 °C in air. The water contact angle was reduced under visible light to a much greater extent for the carbon-free sample. The antimicrobial performance of the coatings was marginally enhanced by removing the carbon. While the carbon may be enhancing the visible light PCA of the TiO₂, we conclude that it is also interfering with the transport of radical oxygen species to the bacteria and reducing the active surface area.

医院感染病例的增长是卫生保健机构的当务之急。减少高频触摸表面的交叉污染是关注的关键领域。如果可以对材料进行改性以增加可见光下的光催化活性（PCA），则触摸表面上坚固的TiO ₂涂层可能会降低病原体的生存能力。研究集中在通过使用掺杂剂和金红石型锐钛矿异质结来增加带隙，使用纳米粒子增加活性表面积以及使TiO ₂对碳敏感。我们之前已经报道了11μm厚的纳米锐钛矿和金红石混合相TiO ₂以及在可见光下具有抗菌作用的碳复合涂层（NsARC）。在这里，我们研究了共沉积碳在抗菌性能中的作用。通过脉冲压力金属有机化学气相沉积（pp-MOCVD）在不锈钢和玻璃基板上沉积厚度为4.0-6.0μm的纳米结构锐钛矿涂层，并对一组进行热处理以除去共沉积的非晶碳。空气中500°C的短时热处理不会影响形态，相和附着力。对于无碳样品，在可见光下水接触角减小的程度更大。通过除去碳，涂层的抗菌性能略有提高。虽然碳可能会增强TiO ₂的可见光PCA，我们得出的结论是，这也干扰了自由基氧物种向细菌的运输并降低了活性表面积。