Role of surface water molecules in stabilizing trapped hole centres in titanium dioxide (anatase) as monitored by electron paramagnetic resonance

摘要

A key factor affecting the photo-efficiency of TiO2 is strictly related to the fate of charge carriers, electrons (e(-)) and holes (h(+)), generated upon band gap excitation. In the present paper we point our attention to the nature of the hole trapping sites in the anatase polymorph monitored coupling the conventional continuous wave EPR (CW-EPR) technique with pulse electron nuclear double resonance (ENDOR) experiments. The attention is focused on the role of surface adsorbed water (both in molecular and in dissociated form) in the stabilization of photogenerated hole centres.