1D/2D CoNi-LDH/ZnIn2S4 S-scheme heterojunction for effectively tetracycline degradation under photocatalytic-peroxymonosulfate activation system: DFT calculations and mechanism insights

The coupling of photocatalysis and peroxymonosulfate (PMS) induced advanced oxidation processes can be realized as an efficient strategy for antibiotics-contaminated water purification. However, developing a suitable catalyst with both visible light photo-response and high PMS activation efficiency remains challenging. Here, we employed the simple hydrothermal process to synthesis CoNi-LDH/ZnIn2S4 S-scheme heterojunction, which combines the benefits of visible photocatalysis and massive generation of active oxygen species generated by activating PMS. The results exhibited that the removal efficiency of optimized heterojunction under Light/PMS system reached 90.1 % within 15 min, which were nearly 8.8 and 1.31 times those of single ZIS and CoNi-LDH, respectively. Mechanistic analysis and density functional theory (DFT) calculation indicated that the satisfactory catalytic activity of heterojunction resulted from the synergistic effect between photocatalysis and PMS activation, which facilitates the separation of photogenerated carriers and accelerates the activation of PMS to generate abundant reactive species. Additionally, CoNi-LDH/ZIS heterojunction possess good ant-interference ability, excellent reusability over four cycles, acceptable adaptability in real water environments. Moreover, the toxicity of intermediates and degradation pathways are also investigated. Overall, this work provides new insights into the fabrication of S-scheme photocatalyst in photocatalytic-PMS activation system, which can realize high-efficient purification of antibiotics wastewater.