Enhancement of Charge Separation and NIR Light Harvesting through Construction of 2D–2D Bi4O5I2/BiOBr:Yb3+, Er3+ Z‐Scheme Heterojunctions for Improved Full‐Spectrum Photocatalytic Performance

Abstract

Abstract Developing full‐spectrum photocatalysts with simultaneous broadband light absorption, excellent charge separation, and high redox capabilities is becoming increasingly significant. Herein, inspired by the similarities in crystalline structures and compositions, a unique 2D–2D Bi4O5I2/BiOBr:Yb3+,Er3+ (BI‐BYE) Z‐scheme heterojunction with upconversion (UC) functionality is successfully designed and fabricated. The co‐doped Yb3+ and Er3+ harvest near‐infrared (NIR) light and then convert it into visible light via the UC function, expanding the optical response range of the photocatalytic system. The intimate 2D–2D interface contact provides more charge migration channels and enhances the Förster resonant energy transfer of BI‐BYE, leading to significantly improved NIR light utilization efficiency. Density functional theory (DFT) calculations and experimental results confirm that the Z‐scheme heterojunction is formed and that this heterojunction endows the BI‐BYE heterostructure with high charge separation and strong redox capability. Benefit from these synergies, the optimized 75BI‐25BYE heterostructure exhibits the highest photocatalytic performance for Bisphenol A (BPA) degradation under full‐spectrum and NIR light irradiation, outperforming BYE by 6.0 and 5.3 times, respectively. This work paves an effective approach for designing highly efficient full‐spectrum responsive Z‐scheme heterojunction photocatalysts with UC function.

Keywords

• Bi4O5I2/BiOBr:Yb3+,Er3+
• full spectrum
• photocatalytic performance
• upconversion
• Z‐scheme heterojunctions