A novel photoelectrocatalytic (PEC) system consisting of S-scheme MgO/g-CN photoanode and modified carbon felt (MCF) cathode was designed for efficient degradation of tetracycline, in which photoanode had both efficient photocatalytic performance and activation of HO produced by the MCF cathode. After 30 min of LED irradiation, the PEC system could completely remove tetracycline at cathodic bias of −0.5 V (vs. Ag/AgCl), and the degradation rate constants were 5.3 and 1.5 times that of electrocatalysis and photocatalysis. The charge transfer mechanism of S-scheme MgO/g-CN was verified by experimental studies and DFT calculations. Mg-N coordination was the key to activate HO to produce singlet oxygen (O) and hydroxyl radicals (OH). The PEC system had excellent degradation performance at pH ranges 4–10, which solved the bottleneck that Fenton system is effective at narrow pH range. This study provides new ideas for preparation of bifunctional photoanodes and new insights into the PEC process.

中文翻译：

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基于双功能MgO/g-C3N4 S型异质结光阳极的新型类芬顿系统，可有效降解四环素

设计了一种由S型MgO/g-CN光阳极和改性碳毡（MCF）阴极组成的新型光电催化（PEC）系统，用于有效降解四环素，其中光阳极既具有高效的光催化性能，又能活化MCF产生的H2O。阴极。 LED照射30 min后，PEC系统在-0.5 V（vs. Ag/AgCl）阴极偏压下可以完全去除四环素，降解速率常数分别是电催化和光催化的5.3和1.5倍。通过实验研究和DFT计算验证了S型MgO/g-CN的电荷转移机制。 Mg-N配位是激活H2O产生单线态氧（O）和羟基自由基（OH）的关键。 PEC体系在pH 4~10范围内具有优异的降解性能，解决了Fenton体系在窄pH范围内有效的瓶颈。该研究为双功能光阳极的制备提供了新思路，也为PEC工艺提供了新见解。