Facile electrochemical anodisation for generating nanopores across visible light-responsive cerium-titanium oxide heterojunctions for environmental remediation

Visible-light responsive heterojunctions exhibited unique performance in environmental remediation due to their ability to form complexes with various Lewis bases and a synergetic effect between their constituents. However, the photocatalytic activities of those composites are significantly restricted by low contact between two semiconductors or pore blockage through impregnation. To address these issues, this study introduces sputtered titanium (Ti)-cerium (Ce) bimetallic oxides, developed by facile electrochemical anodisation to fabricate crystalline nanoporous photocatalysts responded under a visible light region. The deposited Ti-Ce islands and their underlying layer were anodised to develop a unique porous structure with a diameter of ∼61 nm. After annealing, the fabricated bimetallic oxides formed crystalline phases and promoted Ti-Ce interfacial contact by decreasing the Ce3+ concentration followed by its higher specific surface area. The photocatalytic activities of Ti-Ce bimetallic oxides were improved by increasing the Ce sputtering power due to promoted Ti-Ce interfacial contact from one side and the transformation of valence state between Ce3+ and Ce4+ from the other. This resulted in the photodegradation efficiency of the heterostructure with the highest loading of the dopant reaching 83% under simulated solar irradiation. The novel heterojunctions prepared in this study with their fascinating performances can be utilised as advanced photocatalysts for many environmental applications.