Integration with MoO3 microrods as precursors for hierarchical polyaniline microtubes and composites for anionic dye removal in water treatment

A facile and effective method was developed to prepare hierarchical polyaniline (PANI) microtubes, PANI microtube-supported MnO2 nanosheets (PANI-MnO2), PANI microtube-supported Fe3O4 nanoparticles (PANI-Fe3O4), and N-doped carbon microtubes encapsulating nickel nanoparticles (NCMTs-Ni). PANI-MnO2 or PANI-Fe3O4 composites were obtained by embedding PANI layers into MoO3 microrods via etching and a subsequent hydrothermal reaction or high temperature decomposition method. In addition, NCMT-Ni composites were obtained by impregnating PANI microtubes in a Ni(NO3)(2) solution followed by carbonization under the protection of a nitrogen atmosphere. Besides, PANI microtubes exhibited excellent adsorption activities for Congo red (CR), which was also further explored by tailoring the thickness of PANI microtubes.