Synergy of Fenton-like property and self-oxygen supply for realizing enhanced near-infrared-driven integrated wastewater treatment

Near-infrared-driven photocatalysis represents the maximized utilization of solar energy and how to enhance its activity is of great significance. To achieve this, we design a synergetic composite of SnFe₂O₄@CaO₂ in this work. CaO₂ layer could react with H₂O to generate H₂O₂ and O₂. Then, SnFe₂O₄ could trigger Fenton-like reaction to convert H₂O₂ to ^[rad]OH and ^[rad]O₂^– for the pollutant degradation, which is a similar process to the advanced oxidation process. Additionally, SnFe₂O₄ is a NIR-responsive photocatalyst, which could convert dissolved oxygen into reactive oxygen species (ROS) under irradiation. Thus, the synergetic action between CaO₂ and SnFe₂O₄ gives a better catalytic outcome. The experimental results demonstrate that ^[rad]OH and ^[rad]O₂^– are the main free radicals of the reaction. The kinetics characteristics of the free radicals generation are examined and a possible photocatalysis degradation mechanism is proposed. Moreover, the SnFe₂O₄@CaO₂ exhibits excellent photocatalytic sterilization performance. Therefore, the SnFe₂O₄@CaO₂ achieved integrated treatment of wastewater.