Incorporating MoFe alloys into reduced graphene oxide as counter electrode catalysts for dye-sensitized solar cells

In this study, MoFe alloy decorated onto reduced graphene oxide (RGO) nanohybrids is successfully synthesized with various volume ratios of Fe to Mo precursors using a dry plasma reduction method at a low temperature and under atmospheric pressure and is introduced for the first time as an electrocatalyst for counter electrodes (CEs) in dye-sensitized solar cells (DSCs). As observed by HRSEM and TEM analyses, MoFe is successfully immobilized on a 3D network structure of RGO. Well-dispersed MoxFe1-x (0 <= x <= 1) NPs ranging in size from 2 to 6 nm are stabilized with RGO after co-reduction of the metal precursor ions and graphene oxide. The developed catalysts are then applied as CEs in DSCs. As a result, the Mo0.7Fe0.3/RGO nanohybrid exhibited the highest electrocatalytic activity, corresponding to the lowest charge transfer resistance of 0.11 Omega, among the electrodes tested. The DSC employing Mo 0.7 Fe 0.3 /RGO CEs exhibits 5.44% efficiency, which is higher than the 1.26, 4.54 and 4.53% efficiency rates for cells using RGO, Mo0Fe1/RGO and MoFe/RGO electrodes, respectively, due to the optimization of the catalytic activity and the electron conductivity of the developed materials. Note that the efficiency of the device using a Pt electrode was 5.36% under identical conditions. This study concludes that the CE based on the MoFe/RGO nanohybrid is a prospective substitute for Pt which can provide new opportunities for advancing high-efficiency DSCs. Furthermore, the developed catalysts can be applied to other applications, such as methanol oxidation and oxygen reduction reactions. (C) 2018 Production and hosting by Elsevier B.V. on behalf of King Saud University.