Research on the enhanced photocatalytic hydrogen production performance of anatase synergistically co-doped with aluminum, zinc and cerium

Abstract

Hydrogen energy is a clean, renewable energy source, yet current production methods suffer from low efficiency. Titanium dioxide (TiO₂)-based photocatalysis offers a promising approach, but performance is limited by weak visible light absorption and high electron–hole recombination rates. This study improved TiO₂'s photocatalytic efficiency through co-doping with aluminum (Al), zinc (Zn), and cerium (Ce). Materials were synthesized via the sol–gel method and characterized using XRD, SEM, XPS, and other techniques. The doped TiO₂ exhibited a bandgap reduction from 3.0 eV to 1.6 eV, resulting in significantly enhanced visible light absorption. The absorption edge wavelength shifted from 412 nm to 766 nm, enabling more efficient use of solar energy. Electrochemical analyses revealed a substantial decrease in charge transfer resistance and a 1567% increase in photocurrent density. Specific surface area increased by 20%, contributing to better catalytic performance. Hydrogen production tests in ethanol solutions showed a remarkable improvement, with the doped TiO₂ producing hydrogen at a rate of 5781.33 μmol (g⁻¹ h⁻¹), far surpassing the 0.011 μmol (g⁻¹ h⁻¹) of undoped TiO₂. Mechanistic studies using EPR, FTIR, and radiotracer techniques confirmed enhanced charge carrier separation and validated the proposed pathways. These findings demonstrate that co-doping TiO₂ with Al, Zn, and Ce is a viable method for significantly improving photocatalytic hydrogen production, paving the way for more sustainable and efficient hydrogen energy technologies.