DEPOSITION OF NICKEL/IRON OXIDE CO-CATALYSTS ONTO TITANIUM DIOXIDE TOWARDS WATER PHOTOLYSIS

Authors

Md Towhidul Islam Tareqe, Western Kentucky UniversityFollow

Publication Date

8-2025

Advisor(s) - Committee Chair

Lawrence Hill, Matthew Nee, Lei Li

Degree Program

Department of Chemistry

Degree Type

Master of Science

Abstract

Photocatalytic water splitting is one potential approach for sustainable hydrogen production, offering an environmentally friendly alternative to fossil fuels. This process typically employs metal–semiconductor hybrid systems, where the semiconductor absorbs sunlight to generate charge carriers, and the metal cocatalyst facilitates charge separation and surface redox reactions. Titanium dioxide (TiO₂) is a widely studied semiconductor due to its stability and abundance, but its limited absorption of the solar spectrum requires the incorporation of efficient cocatalysts. Platinum is regarded as the benchmark cocatalyst due to strong proton binding energy that easily facilitates the reduction of water to produce hydrogen gas. However, its high cost and scarcity drive the search for earth-abundant alternatives.

Recent studies have demonstrated that bimetallic Janus-type nanoparticles composed of nickel and iron oxide (Ni-Fe_xO_y NPs) can be comparable to platinum’s performance in electrochemical systems. However, Ni-Fe_xO_y NPs have not been studied as co-catalysts for photochemical reactions. Here, we synthesized Ni-Fe_xO_y-decorated TiO₂ nanoparticles via photodeposition, targeting the formation of Fe–O–Ni interfaces and these particles were used in water photolysis reactions. Three synthetic routes were explored: sequential deposition (nickel first, then iron oxide; or iron oxide first, then nickel) and simultaneous deposition of both metals. We also synthesized platinum-decorated TiO2 nanoparticles to use for comparison. The nanoparticles were characterized using transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), inductively coupled plasma optical emission spectroscopy (ICP-OES), and powder X-ray diffraction (XRD), confirming successful surface decoration without altering TiO₂ crystallinity.

Photocatalytic performance was evaluated for TiO₂ with and without co-catalysts under 300 W xenon lamp illumination and reaction conditions were optimized. Gas evolution was measured volumetrically with an eudiometer, and gas concentrations were evaluated using a NIST calibrated hydrogen analyzer and gas chromatography (GC). While GC analysis is ongoing due to technical issues, preliminary results suggest that these Ni-Fe_xO_y co-catalysts result in significantly more gas evolution per unit time than bare TiO2. Future work will involve completing gas chromatography measurements, optimizing reaction pH, and exploring the effect of sacrificial reagents. This research provides preliminary evidence for using Ni-Fe_xO_y co-catalysts in place of platinum for solar-driven hydrogen generation.

Disciplines

Chemistry | Education | Materials Chemistry | Physical Sciences and Mathematics

Recommended Citation

Tareqe, Md Towhidul Islam, "DEPOSITION OF NICKEL/IRON OXIDE CO-CATALYSTS ONTO TITANIUM DIOXIDE TOWARDS WATER PHOTOLYSIS" (2025). Masters Theses & Specialist Projects. Paper 3859.
https://digitalcommons.wku.edu/theses/3859