Hydrazine -functionalized perylene diimide integrated Ti3+ self-doped TiO2 heterostructure for visible light-driven photocatalytic H2 evolution

Abstract

Solar light-powered photocatalytic reactions for highly efficient hydrogen evolution remain a formidable challenge. Herein, a hydrazine-functionalized perylene diimide derivative (HPDI) supramolecular aggregates were incorporated into a Ti3+ self-doped TiO2 (Ti3+-TiO2) by solvent mixing method for highly efficient photocatalytic hydrogen production. The integration of HPDI effectively minimized the electron transfer path and improved the photoelectrochemical activity through π-π stacking of perylene core and hydrogen bonding of the terminal moiety with the Ti3+-TiO2. Further, the Ti3+-TiO2 formed by the partial hydrolysis of titanium isopropoxide (TTIP) followed by calcination also introduces Ti3+ bound states in TiO2 forming oxygen vacancies. It is demonstrated that HPDI with π-π stacking structure along with j-aggregation effectively improve the light absorption in the visible region. The photocatalytic studies for hydrogen production showed a successful formation of the step scheme mechanism in HPDI incorporated Ti3+-TiO2 system and it exhibited a superior hydrogen production efficiency of 1390 μmol/g, which is four-folds higher than bare TiO2. Thus, this work paves the way to design molecular structures as efficient photocatalysts for hydrogen production.