Dual integration system endowing two-dimensional titanium disulfide with enhanced triiodide reduction performance in dye-sensitized solar cells

Highlights: • Dual integration system endowing two dimensional TiS₂ nanosheets with enhanced electrochemical performance for I₃⁻ reduction is configured. • The as-made TiS₂-graphene (TiS₂–G) hybrids as counter electrodes for DSSCs deliver a high power-conversion efficiency of 8.80%, outperforming Pt (8.00%). • The high catalytic activity of TiS₂–G hybrids is ascribed to synergetic effects derived from highly electroactive TiS₂ species and conductive G matrix. • Such a composite also manifests excellent electrochemical stability, indicative of great potential for Pt replacement. State-of-the-art dye-sensitized solar cells (DSSCs) usually utilize noble and scarce Pt as counter electrodes to catalyze the reduction of triiodide in electrolyte, which largely hinders the practical applications of DSSCs. Accordingly, alternatives with low cost, excellent electrocatalytic activity, and superior electrochemical stability to Pt are highly sought after. Herein, we report novel two-dimensional titanium disulfide nanosheets assembled and decorated on graphene (TiS₂–G) through an integrated strategy of ball milling and high temperature annealing process. Benefiting from combined characteristics, when firstly applied as counter electrode, the TiS₂–G hybrids demonstrate superior electrocatalytic activity towards the triiodide reduction with a power conversion efficiency of 8.80%, outperforming the Pt reference (8.00%). The high catalytic activity of TiS₂–G hybrids is ascribed to synergetic effects derived from the dual integration system of highly electroactive TiS₂ species and G functioning as conductive matrix. Most importantly, the as-made TiS₂–G hybrids also deliver outstanding electrochemical stability. The present work provides an effective strategy to engineer the highly active and low cost replacement to noble Pt.