Abstract A novel metal-free photocatalyst of g-C3N4/graphene oxide nanocomposite (CNNP/GO) was fabricated by loading g-C3N4 nanoparticles on graphene oxide through electrostatic self-assembly strategy. XRD, FT-IR, SEM, TEM, and PL were adopted to analyze the structure and properties of the CNNP/GO nanocomposite. Photocatalytic activity of CNNP/GO nanocomposite was evaluated by the degradation of methylene blue (MB) under visible-light irradiation. The results show that the nanonization of bulk g-C3N4 widens the band gap of g-C3N4 from 2.75 eV to 3.40 eV, and the obtained CNNP exhibits an obvious blue-shift in the absorption band edge compared with bulk g-C3N4, resulting in the weak response to visible light. Introducing GO into CNNP can efficiently reduce the band gap to 2.55 eV, thereby enhancing the utilization of visible light. Moreover, the GO can be served as an electron acceptor in the CNNP/GO nanocomposite, leading to significantly improvement in separation efficiency of photo-generated carriers. Hence, the best photocatalytic degradation rate of MB over CNNP/GO nanocomposite is about 2 and 6 times higher than that over bulk g-C3N4 and CNNP samples, respectively. Furthermore, this work also indicates that the novel CNNP could be an excellent material to combine with other semiconductors to construct high efficient nanocomposite photocatalyst.

中文翻译：

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具有增强的可见光光催化活性的纳米级分散g-C 3 N 4 /氧化石墨烯复合光催化剂的制备

摘要 通过静电自组装策略将 g-C3N4 纳米颗粒负载在氧化石墨烯上，制备了一种新型的 g-C3N4/氧化石墨烯纳米复合材料（CNNP/GO）的无金属光催化剂。采用XRD、FT-IR、SEM、TEM和PL分析CNNP/GO纳米复合材料的结构和性能。通过在可见光照射下亚甲蓝 (MB) 的降解来评估 CNNP/GO 纳米复合材料的光催化活性。结果表明，块体 g-C3N4 的纳米化使 g-C3N4 的带隙从 2.75 eV 扩大到 3.40 eV，与块体 g-C3N4 相比，得到的 CNNP 在吸收带边缘呈现明显的蓝移，导致对可见光的弱反应。将GO引入CNNP可以有效地将带隙降低到2.55 eV，从而提高可见光的利用率。而且，GO可以作为CNNP/GO纳米复合材料中的电子受体，显着提高光生载流子的分离效率。因此，MB 对 CNNP/GO 纳米复合材料的最佳光催化降解率分别比块状 g-C3N4 和 CNNP 样品高约 2 倍和 6 倍。此外，这项工作还表明，新型 CNNP 可以成为与其他半导体结合构建高效纳米复合光催化剂的优良材料。