Modulating oxygen vacancy concentration on Bi4V2O11 nanorods for synergistic photo-driven plastic waste oxidation and CO2 reduction

Abstract

Sunlight-driven CO₂ reduction coupled with photo-oxidation of plastic waste into value-added chemicals is a very attractive approach towards solving the greenhouse and environmental crisis. Herein, Bi₄V₂O₁₁ nanorods with regulable O-vacancy concentration have been synthesized by the solvothermal method, aiming to provide abundant active sites for CO₂ adsorption and boost the separation of photogenerated carriers. In a dual-function system, gas production (CO) mainly from the CO₂ reduction-half-reaction reaches 64.7 μmol g⁻¹ h⁻¹ on Bi₄V₂O₁₁ with rich oxygen vacancies (V_O-BVO-15) in PET hydrolysis solution under 300 W Xe lamp irradiation, 24.5-fold higher than that in 2 M KOH solution. Moreover, a considerable amount of HCOOH product with a conversion rate of 0.7 mmol g_cata.⁻¹ is also achieved under 5 h of irradiation. Glyoxal (6.9 mmol g_cata.⁻¹) and glyoxylate (3.2 mmol g_cata.⁻¹) are produced mainly from the PET oxidation-half-reaction. This work presents an in-depth study of the development of Bi–O–V photocatalysts through defect engineering for photocatalytic CO₂ reduction and demonstrates a promising strategy for reuse of plastic waste and realizing carbon cycle with low energy consumption.