Engineering the surface properties of titanium dioxide for photocatalysis
C. Dette, C. S. Kley, P. Punke, G. Rinke, J. Čechal, P. Jacobson, S. Rauschenbach, S. Stepanow, S. J. Jung, and K. Kern
TiO2 anatase is the most commonly used photocatalyst. However, the key stumbling block to wider adoption is the large bandgap which only allows harvesting of ultraviolet photons. Using STM/STS in conjunction with DFT calculations, we show that the band gap of anatase TiO2 (101) can be reduced intrinsically through the formation of a Ti-terminated surface phase. Moreover, by studying dye-sensitized anatase surface, we have revealed multi-conformational adsorption and energy level alignment of the photosensitizers which assert the critical role of the anchoring group of dye molecule in the electron injection process.