Fujishima and Honda first adopted the photoelectrochemical water splitting approach to prepare the TiO2 electrode (Fujishima and Honda in Nature 238:5358–5539, 1972). Since then, semiconductor photocatalysis has been recognized as a favorable method to manage the problem of energy and environmental crisis (Mills and Hunte in J Photochem Photobiol A 108:1–35, 1997; Fujishima et al. in J Photochem Photobiol C 1:1–21, 2000; Robert and Malato in Sci Total Environ 291:85–97, 2002; Wang et al. in Energy Environ Sci 7:2831–2867, 2014). When irradiation under light with energy ≥ its band gap, electrons in the semiconductor are excited from valence band (VB) to conduction band (CB), as a result, holes are left in VB (Chen et al. in Chem Rev 110:6503–6570, 2010).