We report polygonal Pd catalysts on carbon black synthesized by means of polyol process in the presence of poly(vinyl pyrrolidone) and NO3-ion. We find that the polygonal Pd/C has dominant {1 1 1} facets observed by X-ray diffraction method and transmission electron microscopy analysis. The current density for formic acid electrooxidation of polygonal Pd/C (1.908 mA cm(-2)) with controlled surface structures such as dominant {1 1 1} facets is much higher than Pd/C (0.478 mA cm(-2)) at 0 V. Furthermore, the polygonal Pd/C with controlled surface structures shows much improved performances in dye-sensitized solar cells (DSSCs) due to its highly thermal stability and enhanced catalytic activity for iodide reduction. (C) 2009 Elsevier B.V. All rights reserved.