A "user-friendly" chemical approach towards paramagnetic cobalt phosphide hollow structures:: Preparation, characterization, and formation mechanism of Co2P hollow spheres and tubes

User-friendly chemistry principles have been implemented for the synthesis of hollow Co2P structures. In comparison with the original organometallic approach, the resulting alternative route is safe, simple, and inexpensive. The X-ray diffraction (XRD) pattern, X-ray photoelectron spectra (XPS), field emission scanning electron microscope (FESEM) images, and transmission electronic microscope (TEM) images were used to characterize the products, which exhibit paramagnetic behavior down to 2 K, as determined with a commercial superconducting quantum interference device (SQUID) magnetometer. The experimental investigations suggest that the formation of Co2P hollow structures, hollow spheres, and tubes can be explained by an aggregation mechanism and a thermodynamically governed regime. Initially formed Co2P nanoparticles are driven to aggregate into Co2P hollow spheres by the gas bubbles produced. The formation of Co2P tubes then occurs from the hollow spheres via hollow vessels in a thermodynamically governed process. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005).