King David M, Liang Xinhua, Burton Beau B, Kamal Akhtar M, Weimer Alan W
Department of Chemical and Biological Engineering, University of Colorado, UCB 424, Boulder, CO 80309-0424, USA.
Nanotechnology. 2008 Jun 25;19(25):255604. doi: 10.1088/0957-4484/19/25/255604. Epub 2008 May 15.
Pigment-grade TiO(2) particles were passivated using nanothick insulating films fabricated by atomic layer deposition (ALD). Conformal SiO(2) and Al(2)O(3) layers were coated onto anatase and rutile powders in a fluidized bed reactor. SiO(2) films were deposited using tris-dimethylaminosilane (TDMAS) and H(2)O(2) at 500 °C. Trimethylaluminum and water were used as precursors for Al(2)O(3) ALD at 177 °C. The photocatalytic activity of anatase pigment-grade TiO(2) was decreased by 98% after the deposition of 2 nm SiO(2) films. H(2)SO(4) digest tests were performed to exhibit the pinhole-free nature of the coatings and the TiO(2) digest rate was 40 times faster for uncoated TiO(2) than SiO(2) coated over a 24 h period. Mass spectrometry was used to monitor reaction progress and allowed for dosing time optimization. These results demonstrate that the TDMAS-H(2)O(2) chemistry can deposit high quality, fully dense SiO(2) films on high radius of curvature substrates. Particle ALD is a viable passivation method for pigment-grade TiO(2) particles.
使用通过原子层沉积（ALD）制备的纳米厚绝缘膜对颜料级TiO₂颗粒进行钝化处理。在流化床反应器中，将保形的SiO₂和Al₂O₃层涂覆在锐钛矿型和金红石型粉末上。在500°C下，使用三（二甲基氨基）硅烷（TDMAS）和H₂O₂沉积SiO₂膜。在177°C下，使用三甲基铝和水作为Al₂O₃原子层沉积的前驱体。在沉积2nm SiO₂膜后，锐钛矿型颜料级TiO₂的光催化活性降低了98%。进行了H₂SO₄消化试验以证明涂层无针孔，并且在24小时内，未涂覆的TiO₂的TiO₂消化速率比涂覆SiO₂的快40倍。使用质谱法监测反应进程并优化加料时间。这些结果表明，TDMAS-H₂O₂化学方法可以在高曲率半径的基材上沉积高质量、完全致密的SiO₂膜。颗粒原子层沉积是一种用于颜料级TiO₂颗粒的可行钝化方法。
