Abstract: Synchronous illumination X-ray photoelectron spectroscopy (SIXPS) was employed for the first time to directly identify the photogenerated charge separation and transfer on anatase TiO₂ single-crystals with selectively etched {001} facets. More specifically, for the TiO₂ crystals with intact {001} and {101} facets, most of photo generated charge carriers rapidly recombined, and no evident electron hole separation was detected. With selectively etching on {001} facets, high efficient charge separation via hole transfer to titanium and electron to oxygen was clearly observed. However, when the {001} facets were completely etched into a hollow structure, the recombination for photogenerated electron hole pairs would dominate again. These demonstrations dearly reveal that the appropriate corrosion on {001} facets could facilitate more efficient electron hole separation and transfer. As expected, the optimized TiO₂ micro crystals with etched {001} facets could achieve a hydrogen generation rate of 74.3 mu mol/h/g, which is nearly 7 times higher than the intact-TiO₂ crystals.

KeyWords Plus: PHOTOCATALYTIC PROPERTIES; SINGLE-CRYSTALS; LITHIUM STORAGE; NANOSHEETS; PERCENTAGE; ULTRATHIN; GROWTH

Published in JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 138 (9):2917-2920; 10.1021/jacs.5b12521 MAR 9 2016