Hierarchical Fe3O4-reduced graphene oxide nanocomposite grown on NaCl crystals for triiodide reduction in dye-sensitized solar cells

Cost-effective reduced graphene oxide sheets decorated with magnetite (Fe 3 O 4 ) nanoparticles (Fe 3 O 4 -rGO) are successfully fabricated via a chemical vapor deposition (CVD) technique using iron (III) nitrate as an iron precursor, with glucose and CH 4 as carbon sources, and NaCl as a supporting material. TEM analysis and Raman spectroscopy reveal hierarchical nanostructures of reduced graphene oxide (rGO) decorated with Fe 3 O 4 nanoparticles. Fe K -edge x-ray absorption near edge structure (XANES) spectra confirm that the nanoparticles are Fe 3 O 4 with a slight shift of the pre-edge peak position toward higher energy suggesting that the fabricated Fe 3 O 4 nanoparticles have a higher average oxidation state than that of a standard Fe 3 O 4 compound. The hierarchical Fe 3 O 4 -rGO is found to exhibit an excellent catalytic activity toward the reduction of triiodide to iodide in a dye-sensitized solar cell (DSSC) and can deliver a solar cell efficiency of 6.65%, which is superior to a Pt-based DSSC (6.37%).