Zn₄B₆O₁₃: Efficient Borate Photocatalyst with Fast Carrier Separation for Photodegradation of Tetracycline

Abstract

There is a need for photocatalysts with efficient photocarrier separation to address issues with environmental pollution. Photocarrier separation is largely determined by the orbital composition near the band edge. Here, we investigate Zn₄B₆O₁₃ as an efficient photocatalyst for photodegradation of tetracycline. Theoretical calculations of Zn₄B₆O₁₃ show that the valence band near the Fermi level is composed of d and p orbitals whereas the bottom of the conduction band is composed of s and p orbitals; thus, a large value of <i>m</i>_h^<i>*</i>/<i>m</i>_e^<i>*</i> is derived from the band dispersion. The characteristics of this orbital composition promote separation of photoexcited carriers, leading to a high transfer efficiency of the catalyst. Moreover, photodegradation experiments demonstrate that the photocatalytic activity of Zn₄B₆O₁₃ is approximately 5.2 times as high as that of SnO₂. This study provides insights that might aid the development of novel borate-based environmental photocatalysts with superior performance.