Dynamic charge transfer through Fermi level equilibration in the p-CuFe2O4/n-NiAl LDH interface towards photocatalytic application

Abstract

To ensure effective charge transfer dynamics at the interface of a double semiconductor system, a set of p–n heterojunction (p-CuFe₂O₄/n-NiAl-LDH) photocatalysts with varying LDH content was successfully designed through the co-precipitation method. The existence of strong coulombic interactions between the OH⁻ ions present on the surface of the LDH and the defect sites of CuFe₂O₄ were characterized by various instrumental techniques. The p-type and n-type behaviours of the semiconductors were confirmed from antidirectional asymmetric photocurrent measurements. The close interaction between the n-type NiAl LDH and p-type CuFe₂O₄ has been confirmed from the XRD, XPS and HRTM analysis. The visible light induced photocatalytic performances of the synthesized photocatalysts were investigated for Cr(VI) reduction and H₂ evolution. The excellent photocatalytic activity of 50% NiAl LDH–CuFO was observed; i.e. Cr(VI) (93%) reduction at 20 ppm/1 h and H₂ (345.76 μmol h⁻¹) evolution were 6.24 and 3.78 times higher, respectively, as compared to neat NiAl LDH under solar light irradiation. This view point of the rational design of NiAl-LDH/CuFe₂O₄ photocatalyst has potential as a promising material in its contribution towards energy and environment.