Enhanced decoloration efficacy of electrospun polymer nanofibers immobilized with Fe/Ni bimetallic nanoparticles

Colloidal Fe/Ni bimetallic nanoparticles (NPs) have been applied as important materials for environmental remediation applications; however, the reusability of the colloidal Fe/Ni NPs still remains a great issue that limits their environmental applications. In this paper, we developed two different routes to synthesize and immobilize Fe/Ni bimetallic NPs using electrospun polyacrylic acid/polyvinyl alcohol nanofibers as nanoreactors: (1) synthesis of Fe NPs followed by post-coating Ni on Fe NPs (referred to post-coated Fe/Ni NPs) and (2) co-reduction of nickel and iron precursors within the nanofibers (referred to co-reduced Ni/Fe NPs). The formed electrospun nanofibrous mats containing Fe/Ni bimetallic NPs were characterized via different techniques. The decoloration efficiency of the two kinds of Fe/Ni NP-containing nanofibrous mats was compared with that of single metal zero-valent iron NP-containing nanofibrous mats. We show that the co-reduced Fe/Ni NP-containing nanofibrous mats have much higher decoloration efficiency than the single iron NP-immobilized polymer mats; whereas the mats containing post-coated Fe/Ni NPs have lower decoloration efficiency than the single iron NP-containing mats. The formed co-reduced Fe/Ni NP-containing polymer nanofibers can be reused for at least 4 times with high decoloration efficiency. With the easiness of formation and convenient reusability and recyclability, the bimetallic NP-containing polymer nanofibers could be applied in different potential applications including environmental remediation, fuel cells, and electrochemical sensors.