Palladium thorn clusters as catalysts for electrooxidation of formic acid

Pure palladium thorn clusters were synthesized using the electrodeposition method. The clusters were composed of several thorns growing on one basis. Each thorn was composed of hexahedral units with decreasing sizes. The whole thorn was a single crystal along the < 220 > direction. The cluster was synthesized by square wave electrodeposition. By changing the deposition factors, a mixture of thorns and particles was synthesized, where each thorn grew on one basis and the thorn was composed of dodecahedral bases. Compared with the mixture, the cluster had higher activity toward the electrooxidation of formic acid, and also much higher activity than Pd powder, which was evidenced by the improved current density and onset potential of formic acid oxidation. The fact that pure thorn clusters had a higher catalytic activity than the mixture of thorns and particles proved that the higher activity was ascribed to the single crystal property of the thorns.