Polyoxometalate-derived multi-component X/W2C@X, N-C (X=Co, Si, Ge, B and P) nanoelectrocatalysts for efficient triiodide reduction in dye-sensitized solar cells.

Multi-component tungsten carbide based hybrid materials featuring different heteroatoms dopants coated with X, N dual-doped carbon layer (X/W 2 C@X,N-C, XWXNC) are prepared by selecting keggin-type polyoxometalates (POMs) (NH 4 ) n [XW 12 O 40 ] (X=Co, Si, Ge, B and P) and dicyandiamide (DCA) as precursors, and the electrocatalytic activity of these nanocomposites as counter electrode catalysts for dye-sensitized solar cells (DSSCs) are systematically investigated. X-ray diffraction, X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy show that X, N heteratoms have been successfully introduced into the W 2 C and carbon frameworks. The obtained X, N dual-doped carbon layer modified and loaded with W 2 C nanoparticles promotes the improvement of catalytic performance by a synergistic effect. The consequence of photoelectric conversion efficiency ( PCE ) is CoWCoNC (6.68%) > SiWSiNC (6.56%) > GeWGeNC (6.49%) > BWBNC (6.45%) > PWPNC (6.20%)> WNC (6.05%). With the increase of electronegativity of dopants, the photovoltaic performance decrease in a reverse order. This work provides a shortcut for rationally designing high-efficient and cost-effective catalysts for DSSCs.