Large area (9 × 9 cm2) electrostatically sprayed nanocrystalline zincite thin films for hydrogen production application

Synthesis of single phase nanocrystalline zinc ferrite (zincite) thin films that provides high surface area for active redox reactions is reported. Electrostatic spray method is employed for obtaining these ferrite films onto a stainless steel substrate of 9 × 9 cm2 area using zinc acetate and iron nitrate precursor solutions, mixed in 1:1.5 proportions in triply-distilled water. Single zinc ferrite phase in films, confirmed from the X-ray diffraction pattern, reveals the aggregation of several nanometer-sized spherical grains. About 4 nm average roughness is obtained from the 3D AFM image. Zinc ferrite film deposited onto a glass substrate shows both direct (2.96 eV) and indirect (1.92 eV) band gap energies. Hydrophilic behavior that might facilitate easy reaction kinetics in a water splitting process is noticed. Finally, 450 mL/h hydrogen production rate is confirmed when zinc ferrite film electrode was used as an anode in presence of Pt mesh as a cathode.