ABSTRACT In the present study, for the first time, a magnetic graphitic carbon nitride doped with selenium (Se-g-C3N4/Fe3O4) nanocomposite was designed and fabricated by incorporation of selenium to g-C3N4 via a facile thermal condensation technique and hybridization with Fe3O4 nanoparticles. The prepared Se-g-C3N4/Fe3O4 nanocomposite was then applied as ideal catalyst support for the immobilization of copper nanoparticles to prepare the Se-g-C3N4/Fe3O4/Cu nanocatalyst. The structure of Se-g-C3N4/Fe3O4/Cu was comprehensively identified by different spectroscopic and microscopic analyses like FT-IR, TGA, XPS, XRD, VSM, EDX, EDX mapping, FE-SEM, and AAS. The as-fabricated nanocomposite exhibited high catalytic performance in the three-component reaction using various aldehydes, secondary amines, and terminal alkynes and the corresponding propargylamines were gained in good to excellent yields (65-98%) under solvent-free conditions at 110 °C for 3.5 h. Also, this copper nanocatalyst exhibited good stability and could be easily separated using an external magnetic field and reused four times with a slight decrease in its activity. The excellent catalytic performance and stability of the nanocatalyst can be related to the effective interaction between the support and the well-dispersed copper nanoparticles.

中文翻译：

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磁性硒掺杂石墨氮化碳纳米复合材料作为稳定 Cu NPs 的有效催化剂载体

摘要 在本研究中，首次设计和制造了一种掺杂硒的磁性石墨碳氮化物 (Se-g-C3N4/Fe3O4) 纳米复合材料，通过简单的热缩合技术将硒掺入 g-C3N4 并与Fe3O4 纳米颗粒。然后将制备的 Se-g-C3N4/Fe3O4 纳米复合材料用作固定铜纳米颗粒的理想催化剂载体，制备 Se-g-C3N4/Fe3O4/Cu 纳米催化剂。Se-g-C3N4/Fe3O4/Cu的结构通过FT-IR、TGA、XPS、XRD、VSM、EDX、EDX图谱、FE-SEM和AAS等不同的光谱和显微分析进行综合鉴定。制备的纳米复合材料在使用各种醛、仲胺、在无溶剂条件下，在 110°C 下 3.5 小时，末端炔烃和相应的炔丙胺以良好到极好的收率（65-98%）获得。此外，这种铜纳米催化剂表现出良好的稳定性，可以使用外部磁场轻松分离并重复使用四次，其活性略有下降。纳米催化剂优异的催化性能和稳定性可能与载体与分散良好的铜纳米粒子之间的有效相互作用有关。