Boosting photocatalytic efficiency with ohmic contact: A novel Bi/BaTiO3 composite for nitrogen fixation and RhB degradation

This study prepared a novel Bi/BaTiO3 composite photocatalyst featuring an ohmic contact structure by combing the molten salt and solvothermal methods. When irradiated with simulated sunlight, the Bi/BaTiO3 composite demonstrated excellent photocatalytic performance in both photochemical nitrogen fixation (PNF) and photodegradation of RhB. The optimal 6 % Bi/BaTiO3 catalyst exhibited a PNF rate of 309.9 μmol L−1 g−1 h−1, 2.74 times higher than that of pure BaTiO3, and a photodegradation rate constant for RhB 4.13 times that of pure BaTiO3. The morphology, structure, optical properties, and photoelectrochemical properties of the synthesized Bi/BaTiO3 composite were comprehensively studied using various characterization techniques. Results indicated that Bi particles were randomly dispersed among BaTiO3 nanorods. Density functional theory analysis revealed that BaTiO3 has a higher work function than Bi, causing electrons to migrate from Bi to BaTiO3 and forming an ohmic contact structure. Driven by the built-in electric field and band bending, photogenerated electrons in the BaTiO3 conduction band quickly inject into the Bi metal, thereby enhancing charge carrier separation efficiency. Due to the relatively large particle size of Bi, its surface plasmon resonance effect is weak. The excellent photocatalytic performance of Bi/BaTiO3 is primarily attributed to the high carrier separation efficiency conferred by the ohmic contact structure. This study offers valuable insights into designing and synthesizing new photocatalysts for PNF and RhB photodegradation. •Bi/BaTiO3 composite with ohmic contact was synthesized via a combined method.•The ohmic contact structure significantly improves charge carrier separation.•The optimal Bi/BaTiO3 catalyst achieved 2.74 times higher PNF rate than BaTiO3.•The optimal Bi/BaTiO3 degraded RhB 4.13 times faster than BaTiO3.