Ruddlesden-Popper compounds (SrO)(LaFeO3)n (n = 1 and 2) as p-type semiconductors for photocatalytic hydrogen production

Here we report two Ruddlesden-Popper type ferrite perovskites (SrO)(LaFeO3)n (n = 1 and 2) which demonstrate p-type semiconductivity. Their crystal structure, optical absorption and other physicochemical properties have been systematically explored. Our results show that both ferrites crystallize in tetragonal symmetry with structural lamination along c axis. Efficient photocatalytic hydrogen production has been achieved for both samples under full range and visible light illumination. Better performance is noticed for LaSrFeO4 with apparent quantum efficiency approaches 0.31% and 0.19% under full range and visible light illumination, respectively. The p-type semiconductivity is verified by their cathodic photocurrent as well as negative Mott-Schottky slop during Photoelectrochemical measurement. The relative lower activity for La2SrFe2O7 compared to LaSrFeO4 is likely due to its higher defect concentration which facilitates charge recombination. Both compounds exhibit anisotropic phenomenon for charge migrations according to theoretical calculations. Their p-type semiconductivity, strong visible light absorption, chemical inertness and high abundance of constituent elements signify promising applications in the field of solar energy conversion and optoelectronics.

Two layered ferrites LaSrFeO4 and La2SrFe2O7 have been investigated which demonstrate interesting p-type semconductivity and efficient hydrogen production from water.148