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.