A new nanostructure of magnetic–fluorescent bifunctional Janus nanobelts with Fe₃O₄/PMMA as one half and Tb(BA)₃phen/PMMA as the other half has been successfully fabricated by a specially designed parallel spinneret electrospinning technology. The morphology and properties of the final products were investigated in detail by X-ray diffractometry (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), biological microscopy (BM), vibrating sample magnetometry (VSM) and fluorescence spectroscopy. The results revealed that the [Fe₃O₄/PMMA]//[Tb(BA)₃phen/PMMA] magnetic–fluorescent bifunctional Janus nanobelts possess superior magnetic and fluorescent properties due to their special nanostructure. Compared with Fe₃O₄/Tb(BA)₃phen/PMMA composite nanobelts, the magnetic–fluorescent bifunctional Janus nanobelts provided better performance. The new magnetic–fluorescent bifunctional Janus nanobelts have potential applications in novel nano-bio-label materials, drug target delivery materials and future nanodevices due to their excellent magnetic–fluorescent properties, flexibility and insolubility. Moreover, the construction technique for the Janus nanobelts is of universal significance for the fabrication of other multifunctional Janus nanobelts.

G-C₃N₄ with enhanced photocatalytic activity and high yield is synthesized by a one-step pyrolysis method of melamine in a sealed crucible.