A composite photocatalyst comprising ZIF-67 and ZIF-8 was synthesized using a hydrothermal method. The process entailed the crystallization of ZIF-67 on the ZIF-8 dodecahedron backbone, eschewing the utilization of ligands. The photocatalytic efficiency of the composite ZIF-67-on-ZIF-8 was evaluated through the degradation of oxytetracycline hydrochloride (OTC) under visible and UV light. The results indicated superior OTC degradation compared to pure ZIF-8 and ZIF-67, which might be attributed to the energy level and lattice alignment between ZIF-8 and ZIF-67. This facilitated the separation and transfer of photogenerated electron-hole pairs, thereby suppressing electron-hole complexation. The activation of ZIF-67-on-ZIF-8 with peroxymonosulfate (PMS) resulted in a further enhancement in the degradation efficiency of OTC under both visible and UV light conditions. The optimal effect was observed with the addition of 0.6 mmol of PMS, which resulted in a degradation rate of 95.7 % at 60 min under visible light and 97.01 % at 30 min under UV light. The acceleration of the degradation process and the reduction in the required time were the result of a change in configuration. The study’s originality led to the transformation of the conventional type II heterojunction model into the S-scheme heterojunction model through the modification of the light source, thereby offering a novel perspective for heterojunction design.

中文翻译：

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揭示由定向附着机制形成的ZIF-67-on-ZIF-8核壳结构十二面体从II型到步骤方案的转变，以增强盐酸土霉素的光催化降解


采用水热法合成了包含ZIF-67和ZIF-8的复合光催化剂。该过程需要 ZIF-67 在 ZIF-8 十二面体主链上结晶，避免使用配体。通过在可见光和紫外光下降解盐酸土霉素（OTC）来评估复合材料 ZIF-67-on-ZIF-8 的光催化效率。结果表明，与纯 ZIF-8 和 ZIF-67 相比，OTC 降解能力更强，这可能归因于 ZIF-8 和 ZIF-67 之间的能级和晶格排列。这有利于光生电子-空穴对的分离和转移，从而抑制电子-空穴络合。用过一硫酸盐 (PMS) 激活 ZIF-67-on-ZIF-8 可以进一步提高可见光和紫外光条件下 OTC 的降解效率。添加 0.6 mmol PMS 后观察到最佳效果，可见光下 60 分钟的降解率为 95.7%，紫外光下 30 分钟的降解率为 97.01%。降解过程的加速和所需时间的减少是配置变化的结果。该研究的独创性在于通过光源的修改将传统的II型异质结模型转变为S型异质结模型，从而为异质结设计提供了新的视角。