Development of a stable and high-performance Z-scheme In2O3/TiO2 heterojunction photocatalyst for tetracycline degradation

• Z-Scheme In 2 O 3 /TiO 2 heterojunction photocatalyst was constructed. • The photocatalyst has good electron-hole separation efficiency and stability. • The photocatalyst degraded tetracycline well under visible-light conditions. • The photocatalytic mechanism of the photocatalyst was elucidated. Z-scheme heterojunction photocatalysts are generally known for their enhanced capabilities in charge separation, which contribute to improved photocatalytic efficiency. Tetracycline (TC), a prevalent contaminant in water, was degraded using a stable and efficient Z-scheme heterojunction photocatalyst (In 2 O 3 /TiO 2 -calcine) obtained by a combination of hydrothermal and calcination techniques. With a photodegradation efficiency of more than 97 % in 60 min, In 2 O 3 /TiO 2 -calcine demonstrated exceptional catalytic activity and stability in the degradation of TC. In 2 O 3 /TiO 2 -calcine showed not only good electron-hole separation efficiency but also good photoresponse. The main active species in the photocatalytic degradation of TC by In 2 O 3 /TiO 2 -calcine were identified as h + , 1 O 2 and · O 2 - . h + did not directly interact with the pollutant but influenced its degradation by facilitating the generation of 1 O 2 and · O 2 - . The mechanism of the action of the Z-scheme heterojunction was explored in depth from various aspects such as energy band structure and electron transfer paths. The degradation pathways and intermediate products of TC were investigated in this system, revealing that the toxicity of the intermediate products was generally reduced. This study offers new perspectives on Z-scheme heterojunction photocatalyst design and optimization.