Core-shell structured Ni0.85Se@MoS2 nanosheets anchored on multi-walled carbon nanotubes-based counter electrode for dye-sensitized solar cells

The luxury price and scarcity of noble platinum (Pt) hamper its commercialization in dye-sensitized solar cells (DSSCs). Hence, developing cheap, earth-abundant, and easily available electrocatalyst in lieu of Pt is of great current priority for DSSCs. Herein, core-shell structured Ni0.85Se@MoS(2 )nanosheets anchored on carboxylic functionalized multi-walled carbon nanotubes (denoted as Ni0.85Se@MoS2@MWCNTs) were prepared via two-step hydrothermal method combined with probe-sonication process. The resultant of Ni0.85Se@-MoS2@MWCNTs was successfully characterized by XRD, FESEM, TEM, Raman, and BET analysis. Benefiting from the larger surface areas and more electrolyte adsorption sites, the prepared Ni0.85Se@MoS2@MWCNTs exhibited excellent electrocatalytic performance, electrical conductivity, and electrochemical stability when applied as the counter electrode (CE) for DSSCs. More concretely, the DSSCs assembled with Ni0.85Se@-MoS2@MWCNTs delivered remarkable power conversion efficiency (PCE) of 8.98%, exceeding the cell based on Pt CE (6.86%). The combination of Ni0.85Se@MoS2 core-shell structure and MWCNTs provided more active sites, remarkable electric conductivity, and an admirable catalytic property toward the reduction of triiodide. This research suggests a cost-effective strategy to exploring highly effective and robust non-precious-metal CE for their potential application in next-generation energy storage and conversion devices such as DSSCs, water splitting, fuel cells, and other electrochemical applications.