Design and synthesis of an S-scheme TiO2 homojunction with an adjusted, well-defined phase for directional carrier transfer in solar water splitting

The rational design and controlled synthesis of nanoarchitectures is an important strategy for understanding structure-activity relationships. Herein, a novel tufted nanoneedle embedded localized microsphere (TELM) nanoarchitecture is proposed, that is, tufted rutile TiO2 nanoneedles are embedded on the localized surface of anatase TiO2 microspheres (TiO2-TELM). The decay lifetime of photogenerated charge carriers (PCCs) in TiO2-TELM could be prolonged by 38.8% and 34.8% relative to that in pure rutile and anatase TiO2, respectively. Particularly, TiO2-TELM with a 1 wt% Pd loading could deliver an ultrahigh H-2 production rate value of 816.0 mu mol g(-1) h(-1) in pure water. Moreover, photogenerated e(-) and h(+) in TiO2-TELM migrate toward the rutile and anatase phases of TiO2, respectively. This study provides an effective nanoarchitecture synthesis strategy for solving the paradoxical process of increasing the size of dispersed phase nanoparticles and maintaining the substrate surface area.