Synthesis of NiCo2S4 nanowire arrays through ion exchange reaction and their application in Pt-free counter-electrode

• NiCo2S4 nanowire arrays have been fabricated by the ion exchange reaction.
• The solution-based IER avoids use of high temperatures and toxic gas sources.
• NiCo2S4 nanowire arrays exhibit outstanding I−/I3− redox catalytic activity.
• Excellent electrocatalytic characteristic make NiCo2S4 competitive as counter-electrodes.

Self-standing NiCo2S4 nanowire arrays have been fabricated on FTO substrate by the ion exchange reaction (IER) and directly used as the counter-electrode for dye-sensitized solar cells. The solution-based IER avoids use of high temperatures and toxic gas sources such as H2S during the synthesis process. The cyclic voltammetry (CV) tests show that the NiCo2S4 nanowire arrays exhibit better electrocatalytic property than Pt. The DSSC using NiCo2S4 nanowires arrays as the counter-electrode achieves a power conversion efficiency of 5.38%, which was comparable with Pt counter-electrode (5.92%).The synthesis simplicity, low cost, and excellent electrocatalytic characteristic make the NiCo2S4 nanowire array competitive as counter-electrodes in DSSCs.