报告题目：Black Titanium Dioxide: A New Engineered Nanoparticle for photocatalysis

报 告 人：Peter Y Yu， Department of Physics，University of California, Berkeley

报告时间：10月29日（周一）14:30

报告地点：理科楼郑裕彤讲堂

报告摘要：TiO2 is almost an ideal photocatalyst in that it is stable and relatively inexpensive. Unfortunately its large band gap (>3.0eV) makes it inefficient for photocatalysis with solar radiation. As a result there have been many attempts to reduce the band gap of TiO2 by doping with impurities. These attempts have reduced the band gap to the visible at most. Recently a breakthrough has been achieved which succeeded in converting white TiO2 nanocrystals into a black TiO2 powder with an absorption edge reduced to 1.2 eV. [ Xiaobo Chen, Lei Liu, Peter Y. Yu, and Samuel S. Mao. Increasing Solar Absorption for Photocatalysis with Black Hydrogenated Titanium Dioxide Nanocrystals. Science 331, 746 (2011).] This black TiO2 powder has demonstrated enhanced efficiency in photocatalysis under solar irradiation. High resolution transmission electron microscopy has shown that the black TiO2 nanoparticles consist of an anatase core surrounded by a disordered shell. Since the appearance of these pioneering results, black TiO2 in other forms such as nanowires have also been fabricated. However, the exact nature of the disordered shell in black TiO2 remains unknown. In this talk I shall present recent experimental and theoretical results which shed light on the structural, chemical and electronic properties of black TiO2 powder.