Porous chalcogels CoMoS 4 and NiMoS 4 made by a facile solution reaction displayed good electrocatalytic activity in the redox reaction of the I À /I 3 À shuttle. Dye-sensitized solar cells with these ternary compounds as counter electrodes (CEs) showed photovoltaic performance similar to the devices made with noble metal platinum CE (7.46%).Dye-sensitized solar cells (DSSCs) have attracted significant attention as low-cost alternatives to traditional photovoltaic devices. 1,2 In DSSCs, counter electrodes (CEs) with both excellent electrocatalytic activity and high electrical conductivity are indispensable to obtain a low overvoltage and to accelerate the regeneration of I À from I 3 À . Due to the fact that noble metal Pt, the most widely used material for CEs at present, is very expensive, studies have recently been made extensively on low-cost Pt-like alternatives, including carbonbased materials, 3 conducting polymers, 4 and metals in the form of oxides, 5 sulfides, 6-10 selenides, 11 nitrides, 12 and carbides, 13 and great promise has been demonstrated in this field. Extension of the CE materials to ternary compounds may greatly expand this research platform. Catalysts based on molybdenum or tungsten sulfides have been widely used for hydrodesulfurization and hydrogen evolution reaction by electrocatalysis, and introduction of Co or Ni promoters into these matrices results in significant enhancement in the catalytic activities. 14-16 Kanatzidis et al. 17 have most recently reported the synthesis of porous CoMoS 4 and NiMoS 4 via facile solution reactions. In this work, we have applied these ternary materials with and without graphite additives as the counter electrodes in DSSCs. The resulting photovoltaic devices showed power conversion efficiency up to 7.31%, comparable to the DSSCs made with an expensive platinum-based counter electrode (7.46%).Ammonium tetrathiomolybdate (NH 4 ) 2 MoS 4 was obtained by the reaction of (NH 4 ) 6 Mo 7 O 24 Á4H 2 O and (NH 4 ) 2 S aqueous solution at ambient temperature. CoMoS 4 and NiMoS 4 were synthesized as previously described. 17 Briefly, Co(NO 3 ) 2 Á6H 2 O, Ni(NO 3 ) 2 Á6H 2 O and (NH 4 ) 2 MoS 4 were dissolved in formamide separately, and then Co or Ni precursor solution was added into the tetrathiomolybdate solution. In these reactions, cationic species of VIII group metals interacted with thiomolybdate anions, leading to precipitation of solids. As the polymerization proceeded, the viscosity of the solution increased, which eventually solidified to a monolithic black gel. It took 7-14 days for the viscous solution to transform into a rigid gel. The products were then annealed at 300 1C in a nitrogen atmosphere and characterized by X-ray powder diffraction, X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS), scanning and high-resolution transmission electron microscopy (HRTEM).Both Ni-and Co-based chalcogels were found to be amorphous, as indicated by the predominant broad features in the XRD patterns (Fig. S1, ESI †). A similar resu...