**2.3 Carbon nanofibers as supporting materials**

Carbon nanofibers with unique and tunable morphology have been used in catalytic, environmental, and energy applications [24]. Polyacrylonitrile (PAN) nanofibers have been used extensively as an efficient precursor for CNF fabrication. CNFs have been employed as an efficient carrier for the loading of catalytic and bioactive materials. A broad spectrum of metal oxide nanoparticles has been immobilized in/onto CNFs for dye removal applications. The main approaches to decorate CNFs with active materials include electrodeposition, chemical synthesis, and dry synthesis. Interestingly, the CNFs also present adsorption capacity (**Figure 3II**), due to the binding between aromatic rings of CNFs and adsorbate based on π-π stacking interaction [20]. The high conductive and chemically inert properties of CNFs enhance its application in dye degradation via photocatalysis and promote reusability. The dye molecules have high chances to be attracted to CNFs, having a π-conjugative structure, before being decomposed by photocatalysts loaded on the surface of the nanofibers [25].
