Fe3O4 Nanoparticles, Metal–Organic Framework of Zr and Cu, and their Composites: Synthesis, Characterization, and Photocatalytic Activity

Fe3O4 nanoparticles (a), novel Fe3O4/Zr-MOF (b) and Fe3O4/Cu-MOF (c) composites with Zr and Cu metal-organic framework Zr-MOF (d) and Cu-MOF(e) were synthesized. Fe3O4 nanoparticles Zr-MOF (d) and Cu-MOF (e) were synthesized by hydrothermal method and Fe3O4/Zr-MOF and Fe3O4/Cu-MOF composite was synthesized by sonication. The photocatalytic activity of the Fe3O4 (NPs), MOFs and the composites were investigated for degradation of methylene blue exposed to sunlight at pH 9.2. The composites were characterized by FTIR, UV-vis, TGA, SEM, and EDS spectroscopy. The composites Fe3O4/Zr-MOF and Fe3O4/Cu-MOF showed the highest efficiency of 87% and 96% respectively, whereas nanoparticle Fe3O4 (NPs) exhibited efficiency of 77%. The of MOF, Zr-MOF and Cu-MOF individually showed less efficiency of 41%, and 49% respectively. The composite Fe3O4/Zr-MOF and Fe3O4/Cu-MOF showed 1.13 and 1.24-times higher efficiency respectively over Fe3O4 (NPs) and more than double of MOF. The incorporation of Fe3O4 NPs in the Zr-MOF and Cu- MOF tune the band gap to an optimal level for radical formation and sustain required time to initiate photochemical reaction. The band gap of Fe3O4 (NPs) and Fe3O4/Cu-MOF composite is 1.95 eV and 2.54 eV respectively, whereas the band gap for TiO2 is approximately 3.2 eV which is established photo-catalyst. It is observed that Fe3O4/Cu-MOF (c) composites band gap closer to TiO2 and shows higher efficiency. These composites showed outstanding degradation efficiency than current established photocatalyst. So, these could be used industrial pollution mitigation for green environment.

Reazul Hasan Riyan, Muhaimin Helal Efat, Md. Azharul Arafath and Md. Sohrab Hossain