Enhanced photocatalytic performance of TiO2 through a novel direct dual Z-scheme design

• Published in: Applied surface science 2020-12, Vol.533, p.147506, Article 147506
• Main Authors: Sari, Fitri Nur Indah, Yen, Duong Thi Kim, Ting, Jyh-Ming
• Format: Article
• Language: English
• Subjects: g-C3N4; Photodegradation; TiO2 mesoporous beads; Z-scheme; α-MoO3
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2020.147506

A novel ternary TiO2/MoO3/g-C3N4 nanocomposite photocatalyst exhibiting a dual Z-scheme photodegradation mechanism is reported. The enhanced photocatalytic activities are ascribed to the improved visible light absorption from the α-MoO3 and g-C3N4, and enhanced photogenerated hole/electron separation in the TiO2 and α-MoO3. [Display omitted] •A novel dual Z-scheme TiO2/MoO3/g-C3N4 nanocomposite photocatalyst.•Oxygen vacancies in the TiO2 and MoO3 dominate the photocatalytic performance in the dual Z-scheme.•The g-C3N4 acts as an electron trap to enhance the charge separation efficiencies in the Z-scheme.•The photogenerated hole is the main oxidative species in the photodegradation.•Excellent photodegradation efficiency of methylene blue up to 95%. A novel ternary TiO2/MoO3/g-C3N4 nanocomposite photocatalyst has been synthesized and shown to exhibit a direct dual Z-scheme photodegradation mechanism. The TiO2/MoO3/g-C3N4 nanocomposite catalyst outperforms its constituents for methylene blue degradation. The highest degradation rate constant of 0.0303 min−1 is about 3.9 times greater than that of TiO2. The improved photocatalytic activity is attributed to the enhanced visible light absorption from the g-C3N4 and α-MoO3, enhanced photogenerated hole/electron separation primarily in the TiO2 and α-MoO3, and enhanced fast charge transfer due to the existence of oxygen vacancies. The photodegradation mechanism is explained using a direct dual Z-scheme. This work affords a new insight towards designing highly efficient Z-scheme photocatalysts with enhanced visible light absorption, efficient photogenerated hole/electron separation, and strong redox ability.