Rong-Hua Zhang

Magnetic Properties of CoPt Nanorods with Different Structures

We prepared two kinds of CoPt nanorods by galvanic displacement reaction and chemical reduction. One type was solid (CoPt a) and the other was hollow (CoPt b). Transmission electron microscopy (TEM) and energy dispersive X ray spectroscopy (EDS) were used to characterize the shape and composition of the nanorods. The magnetic properties were measured at 5 and 300 K. The coercivities of the CoPt a and CoPt b nanorods were found to be 6.5 and 9.3 A· m-1 at 5 K, respectively. The coercivities decreased to 0 A· m-1 when the temperature was increased to 300 K. The field cooling (FC) and zero field cooling (ZFC) curves indicated that both the CoPt a and CoPt b nanorods are superparamagnetic. The blocking temperatures (TB) of CoPt a and CoPt b are 10.0 and 9.0 K, respectively. The different magnetic properties of the two kinds of CoPt nanorods including coercivity, magnetization, and blocking temperature may be due to their different compositions and structures.

Studies on the synthesis, dealloying, and electrocatalytic properties of CoPd nanocatalysts

CoPd nanocatalysts were synthesized by a successive reduction using poly(vinylpyrrolidone) as stabilizer. The structure, morphology, and composition of CoPd nanocatalysts were characterized by transmission electron microscopy (TEM), high-resolution TEM, X-ray powder diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), and inductively coupled plasma mass spectrometry (ICP-MS). The CoPd nanocatalysts showed electrocatalytic performance for methanol oxidation in alkaline medium. The electrocatalytic performance was weakened after dealloying process in acidic solution. The balance of the dealloying effect and the alloying effect should be accentuated in this field in the future.