Development of semiconductor catalysts is an attractive way to solve energy shortage and pollution problems. In this work, a kind of ternary heterojunction nanocomposite g-C₃N₄/Co₃O₄/Ag₂O was successfully prepared, whose morphology, structure and composition were characterized by TEM, EDS, XRD and XPS analysis. Photocatalytic experiments prove that g-C₃N₄/Co₃O₄/Ag₂O shows good photodegradation efficiency (98.09%) for RhB under visible light. The free radical capture experiment indicates that the hole, superoxide radical and hydroxyl radical all contribute to the photocatalytic process. In addition, it is found that introducing Ag₂O into the composite can efficiently promote the formation of H₂O₂via the reduction of O₂. An electrochemical oxygen reduction reaction (ORR) study further confirms that the value of electron transfer during the ORR is 2.07 for g-C₃N₄/Co₃O₄/Ag₂O, indicating the promoted two-electron O₂ reduction reaction to H₂O₂. Based on the above results and energy band structures of semiconductors, a possible photocatalysis mechanism is proposed.

中文翻译：

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g-C3N4 / Co3O4 / Ag2O三元异质结纳米复合材料的制备及其光催化活性和机理

半导体催化剂的开发是解决能源短缺和污染问题的一种有吸引力的方法。本文成功地制备了一种三元异质结纳米复合材料gC ₃ N ₄ / Co ₃ O ₄ / Ag ₂ O，并通过TEM，EDS，XRD和XPS对它们的形貌，结构和组成进行了表征。光催化实验证明，gC ₃ N ₄ / Co ₃ O ₄ / Ag ₂O在可见光下对RhB表现出良好的光降解效率（98.09％）。自由基捕获实验表明，空穴，超氧自由基和羟基自由基均对光催化过程有贡献。另外，发现将Ag ₂ O引入到复合物中可以通过减少O ₂来有效地促进H ₂ O ₂的形成。电化学氧还原反应（ORR）研究进一步证实，对于gC ₃ N ₄ / Co ₃ O ₄ / Ag ₂ O，ORR期间的电子转移值为2.07 ，表明存在促进的二电子O _2。还原反应生成H ₂ O ₂。基于以上结果和半导体的能带结构，提出了一种可能的光催化机理。