Designing an S-scheme heterojunction based on MOF-808-NH2 and TpTt-COF for enhanced photocatalytic degradation of alkylphenols under visible light†

Alkylphenols (APs), as endocrine disruptors (EDCs), pose potential threats to aquatic organisms and human health. Their photodegradation efficiency decreases with shorter alkyl chains and branched configurations. MOF-808-NH₂ and TpTt-COFs, serving as photocatalysts, exhibit limited degradation capabilities and suffer from time-consuming and complex traditional synthesis methods. Herein, an S-scheme heterojunction based on MOF-808-NH₂ and TpTt-COFs was synthesized using a time-efficient one-pot hydrothermal method. The findings of this study indicate that the loaded structure (MOF-808-NH₂)₂/(TpTt-COF)₈ (with a weight ratio of 2 : 8) demonstrates over 97% effective photocatalytic removal of six APs (within 120 min), along with excellent stability and photocatalytic performance and broad applicability under visible light. The degradation rate of Zr-MOF₂/TpTt-COF₈ is 2.47 times higher than that of MOF-808-NH₂. The mechanism of this photocatalyst was further verified as an S-scheme heterojunction electron-transfer model, facilitating the efficient separation of charge carriers. Additionally, the degradation pathway was predicted, showing that the toxicity of degradation products to organisms gradually decreases. This study not only provides a feasible approach for the efficient degradation of APs in environmental water, demonstrating advantages and improvements over previous research findings, but also offers new insights for the design of novel visible-light photocatalysts.