Seed-mediated growth of palladium/copper tetrapods on specific activity for oxygen reduction reaction

Abstract

Pd/Cu tetrapods with 2¯24 facets were successfully prepared using the seed-mediated growth method, where Pd and Cu were co-deposited on small cubic Pd seeds (10 nm) in the aging growth solution with a molar ratio for Pd to Cu precursor of 1:1 at 45 °C. The deposition of more Cu atoms caused crystal growth toward 11¯1 owing to the stacking fault and interruption of crystal growth with sequential stacking of Pd atoms. When Pd seeds were grown in the same growth solution using accelerated Pd deposition at a high growth temperature (95 °C), Pd/Cu concave nanocubes (CNCs) were obtained. A Pd/Cu web-like nanostructure formed when the same growth solution was stirred at 45 °C. Additionally, the Tafel results confirmed that the specific activity of Pd/Cu tetrapods was 1.56 and 1.65 times higher than those of the CNCs and webs, respectively.