Abstract Photo-corrosion of Cu2O photocatalyst considered as an important factor extremely restricts its catalytic activity. However, so far, there are few comprehensive reports on the mechanism of photo-corrosion inhibition and stability improvement of Cu2O in photocatalytic degradation. In this work, oxidized g-C3N4/Cu2O@C (GCNOX/Cu2O@C) visible-light catalysts with protective carbon layer were first prepared using the copper-based metal–organic frameworks (HKUST-1) composite as precursors. The UV–visible DRS, PL, XPS valence-band and Mott-Schottky curves were used to characterize that the formation of carbon layer leads to establishing built-in electric field, shifting of energy bands and photogenerated carrier separation. Linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) revealed that GCNOX/Cu2O@C had the strongest photo-response current and the lowest interface contact resistance. The photodegradation activity of GCNOX/Cu2O@C was analyzed for Rhodamine B (RhB) and ciprofloxacin (CIP) under low energy visible light irradiation and the degradation kinetic constants were 0.01413 min−1 and 0.03958 min−1, respectively, which were much higher than other as-prepared catalysts. It also exhibited outstanding stability with the 87.4% degradation efficiency in 90 min after four recycles. Furthermore, the characterization of GCNOX/Cu2O@C after the cyclic reactions further proved the ultra-high stability of the carbonized materials. Additionally, on the basis of degradation experiments and photoelectrochemical results, the possible transfer path of photocarriers between material interfaces, photo-corrosion inhibition mechanism of cuprous oxide and the transformation mechanism of active radicals were proposed. This work provided a novel insight for MOFs-derived composites as a highly efficient and stable visible-light catalyst.

中文翻译：

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介孔八面体 GCNOX/Cu2O@C 抑制光腐蚀作为一种源自氧化 g-C3N4/HKUST-1 复合结构的高效可见光催化剂

摘要 作为重要因素的Cu2O光催化剂的光腐蚀极大地限制了其催化活性。然而，迄今为止，关于Cu2O在光催化降解中的光腐蚀抑制和稳定性提高的机制鲜有综合报道。在这项工作中，首先使用铜基金属有机骨架（HKUST-1）复合材料作为前驱体制备了具有保护碳层的氧化 g-C3N4/Cu2O@C（GCNOX/Cu2O@C）可见光催化剂。紫外可见 DRS、PL、XPS 价带和 Mott-Schottky 曲线用于表征碳层的形成导致建立内置电场、能带移动和光生载流子分离。线性扫描伏安法 (LSV) 和电化学阻抗谱 (EIS) 表明 GCNOX/Cu2O@C 具有最强的光响应电流和最低的界面接触电阻。GCNOX/Cu2O@C 在低能可见光照射下对罗丹明 B (RhB) 和环丙沙星 (CIP) 的光降解活性进行了分析，降解动力学常数分别为 0.01413 min-1 和 0.03958 min-1，远高于此与其他制备的催化剂相比。它还表现出出色的稳定性，在四次循环后 90 分钟内降解效率为 87.4%。此外，循环反应后GCNOX/Cu2O@C的表征进一步证明了碳化材料的超高稳定性。此外，根据降解实验和光电化学结果，提出了光载流子在材料界面之间可能的转移路径、氧化亚铜的光腐蚀抑制机制和活性自由基的转化机制。这项工作为 MOF 衍生的复合材料作为一种高效且稳定的可见光催化剂提供了新的见解。