Removal of Pb2+ and Cd2+ toxic heavy metal ions driven by Fermi level modification in NiFe2O4-Pd nano hybrids

The exact information about the electronic band structure driven by interface in nanohybrid catalysts is critical for its photocatalytic applications. In this perspective, the synthesis of such nanohybrids and understanding its band structure attains significance. Herein, NiFe2O4 synthesized by solvothermal method was chemically linked via 3-Aminopropyl triethoxysilane to Palladium resulting in a nanohybrid NiFe2O4-Pd. The structure, morphology and functionalization of the nanohybrid were confirmed by XRD, TEM, XPS, FTIR and Raman analysis. The super-paramagnetic nanohybrid is tested for the removal of heavy metal ions Pb2+/Cd2+ from water, quantified with Atomic Absorption Spectroscopy. Compared to NiFe2O4, photocatalytic rate constant value of NiFe2O4-Pd got increased from 0.52 x 10(-1) to 1.4 x 10(-1) min(-1) for Pb2+ ions and 0.31 x 10(-1) to 0.86 x 10(-1) min(-1) for Cd2+ ions. The mechanism was studied based on porosity (BET analysis), reactive species and band structure analysis. The Ultraviolet Photoelectron spectroscopy study revealed the role of nanoSchottky barrier in enhancing photocatalytic activity.