Inducing a deep impurity level in Li2SnO3 by ionic Bi–O bonding to enhance light absorption in photocatalysis

Orbital engineering is an important strategy for modulating light absorption in photocatalysis . Here, Bi doping of the oxide photocatalyst Li 2 SnO 3 to enhance light absorption was rationally designed by orbital engineering. Based on density functional theory, owing to the lower Bi 6s energy level compared with that of Sn 5s, a deep impurity energy level induced by ionic Bi–O bonds is generated in the middle band gap of Li 2 SnO 3 . The impurity energy level can facilitate the utilization efficiency of light absorption, leading to remarkably enhanced photocatalytic performance. For Li 2 Sn 0.9 Bi 0.1 O 3 , the photodegradation rate of tetracycline solution reached 76% within 30 min, which was approximately 2.6 times higher than that for Li 2 SnO 3 . A radical trapping experiment revealed that the holes (h + ) play a dominant role in the elimination reaction . Finally, liquid chromatography–mass spectrometry was performed to monitor the photocatalytic process. This study lays a foundation for rational design of photocatalysts with excellent light absorption for photocatalysis .