Cadmium Sulphide Sensitized Crystal Facet Tailored Nanostructured Nickel Ferrite @ Hematite Core-Shell Ternary Heterojunction Photoanode for Photoelectrochemical Water Splitting

Abstract

Design of composite semiconductor nanostructures with proper band alignment for efficient charge separation and carrier transport has been at the center of research for photoelectrochemical water splitting. This work demonstrates the deposition of a NiFe2O4 @Fe2O3 core-shell nanostructured film sensitized with CdS to form a ternary heterojunction for cascade type electron transfer. The hematite nanostructures were grown by hydrothermal approach through dipping into a solution of Nickel Nitrate yielded anchoring of Ni2+ ions on the outer surface. The films were then annealed at 650 0C for the diffusion of Ni2+ ions into the hematite lattice which forms core-shell NiFe2O4 @Fe2O3 heterojunction. The films were further sensitized with CdS nanoparticles deposited by a hydrothermal approach to form the final ternary heterojunction photoanode. Several different nanostructures were grown and the effect of crystal facet tailoring was observed on Ni loading and photoelectrochemical performance. The photoelectrochemical measurements were carried out using a potentiostat under 100 mW/cm2 light source (150W Xenon Lamp) with Pt counter electrode and 0.5 M Na2S and 0.5 M Na2SO3 electrolyte. A current density of 3.47 mA/cm2 was observed at 1.23 V (vs Ag/AgCl). An Applied Bias to Photocurrent Efficiency (ABPE) of 1.8 % photoconversion efficiency was observed using the fabricated electrodes at 0.288V (vs Ag/AgCl).

Solvothermal Etching-Assisted Phase and Morphology Tailoring in Highly Porous CuFe2O4 Nanoflake Photocathodes for Solar Water Splitting

“…Hematite was deposited on FTO-coated glass substrates via a solvothermal method . At first, 30 mL of ethanol was taken in a 100 mL beaker.…”

“…Hematite was deposited on FTOcoated glass substrates via a solvothermal method. 58 At first, 30 mL of ethanol was taken in a 100 mL beaker. 0.15 M solution of FeCl 3 was prepared, followed by adding urea to make a solution of concentration 0.1 M. Five milliliters (5 mL) of acetic acid was added until the solution was clear and no turbidity was present.…”