Abstract Herein, a novel composite photocatalyst was prepared by the vapor deposition of g-C3N4 on TiO2 nanosquare, dominated with {001} facets. The deposition method is robust, convenient, and effective. The surface topography and structure of the composites were analyzed by XRD, XPS, SEM, and TEM. The mechanism for enhanced photocatalysis was studied using PL, PC, UV–vis-NIR-DRS, TRPL, EIS and EPR. The photocatalytic activities of the fabricated composites were evaluated by the degradation of methylene blue (MB) and hexavalent chromium ions (Cr6+) under visible light irradiation. The photodegradation of MB and Cr6+ was completed in 50 and 40 min, respectively. Based on a pseudo-first-order kinetic model (ln(C0/C) = kt), the measured the degradation rate constant for MB using gCN/TO5 was 4.6 and 35.9 times higher than that of pure g-C3N4 and TiO2, respectively. Similar results were found for the Cr6+ degradation. The outstanding photocatalytic performance of the g-C3N4 on TiO2 composite was ascribed to the presence of the TiO2/g-C3N4 heterojunctions, which effectively improved the separation of the photoexcited electrons and holes hence the enhancement of visible-light photoactivity. Overall, this work showed a convenient and efficient method for fabricating the visible light photocatalysts with established possible mechanisms for the photoactivity of the hybrid photocatalytic composite material.

中文翻译：

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g-C3N4 气相沉积在 TiO2 纳米方块上用于在可见光下有效光降解 MB 和 Cr6+

摘要 在此，通过气相沉积 g-C3N4 在以 {001} 面为主的 TiO2 纳米方块上制备了一种新型复合光催化剂。该沉积方法稳健、方便且有效。通过XRD、XPS、SEM和TEM分析了复合材料的表面形貌和结构。使用PL、PC、UV-vis-NIR-DRS、TRPL、EIS和EPR研究了增强光催化的机制。通过在可见光照射下降解亚甲蓝 (MB) 和六价铬离子 (Cr6+) 来评估制备的复合材料的光催化活性。MB 和 Cr6+ 的光降解分别在 50 和 40 分钟内完成。基于准一级动力学模型 (ln(C0/C) = kt)，使用 gCN/TO5 测得的 MB 降解速率常数是纯 g-C3N4 和 TiO2 的 4.6 和 35.9 倍，分别。对于 Cr6+ 降解也发现了类似的结果。g-C3N4 对 TiO2 复合材料的优异光催化性能归因于 TiO2/g-C3N4 异质结的存在，它有效地改善了光激发电子和空穴的分离，从而增强了可见光光活性。总的来说，这项工作展示了一种方便有效的制备可见光光催化剂的方法，并确定了混合光催化复合材料光活性的可能机制。有效地改善了光激发电子和空穴的分离，从而增强了可见光光活性。总的来说，这项工作展示了一种方便有效的制备可见光光催化剂的方法，并确定了混合光催化复合材料光活性的可能机制。有效地改善了光激发电子和空穴的分离，从而增强了可见光光活性。总的来说，这项工作展示了一种方便有效的制备可见光光催化剂的方法，并确定了混合光催化复合材料光活性的可能机制。