Edge-Active Enriched MoS2 Porous Nanosheets as Efficient Pt-Free Catalysts toward the Triiodide Reduction Reaction

Abstract

Developing high-efficiency counter electrode (CE) catalysts for the triiodide (I3–) reduction reaction (IRR) is of great significance for the development of cost-effective dye-sensitized solar cells (DSSCs). From the perspective of further enhancing the catalytic activity of CE catalysts by exposing more active sites, edge-active enriched MoS2 porous nanosheets are elaborately constructed using the as-prepared one-dimensional MoO3 rods and poly(vinylpyrrolidone) (PVP) as a template-directing agent and surfactant based on the dissolution–recrystallization strategy (MoS2-P), respectively, while the MoS2 quasi-particles (MoS2-C) and irregular MoS2 aggregations are also synthesized using cetyltrimethyl ammonium bromide (CTAB) as a surfactant and commercial MoO3 powder as a molybdenum source under similar reaction processes. Benefiting from the high specific surface area, exposure of edge active sites, and effective ion diffusion-favored structure, MoS2-P delivers good photovoltaic performance (PCE = 8.16%, Voc = 0.782 V, Jsc = 16.77 mA/cm2, FF = 0.62) when used as a CE catalyst for DSSCs, superior to that of MoS2-C (PCE = 6.87%, Voc = 0.741 V, Jsc = 15.91 mA/cm2, FF = 0.58), which is comparable with that of the Pt-based device (PCE = 8.33%, Voc = 0.775 V, Jsc = 16.85 mA/cm2, FF = 0.64). A series of electrochemical results further reveal that the obtained MoS2-P has good catalytic activity for the IRR and electrochemical stability in iodine-based electrolytes. Hence, our work may provide a promising catalyst for the energy conversion field.