Engineering the surface properties of titanium dioxide for photocatalysis

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.