Mesocellular carbon foams (MSU-F-Cs) with a high surface area (911 m(2) g(-1)) and large pores (-25 nm) have been used as counter electrodes for CdS/CdSe quantum-dot sensitized solar cells (QD-SSCs). Under 1 sun illumination, the MSU-F-C counter electrode QD-SSC shows a maximum energy conversion efficiency of 1.75%, which is much higher than that of those employing conventional Pt (1.22%) or commercial carbon (0.94%) counter electrodes. Electrochemical impedance spectroscopy analysis shows that the large pores and high surface area of MSU-FC improve the catalytic activity of the counter electrode in polysulfide redox electrolyte. (C) 2010 Elsevier B.V. All rights reserved.