Noncrystalline nickel phosphide (Ni–P) nanoparticles have drawn great attention due to their high potential as catalysts. However, the structure of noncrystalline Ni–P nanoparticles is still unknown, which may shed light on explaining the catalysis mechanism of the Ni–P nanoparticles. In this paper, noncrystalline Ni–P nanoparticles were synthesized. Their morphology, particle size, element contents, local atomic structures, as well as the catalysis in the thermal decomposition of ammonium perchlorate were studied. The results demonstrate that the as-prepared Ni–P nanoparticles are spherical with an average diameter of about 13.5 nm. The Ni and P contents are, respectively, 78.15% and 21.85%. The noncrystalline nature of the as-prepared Ni–P nanoparticles can be attributed to cross-linkage between P-doping f.c.c.-like Ni centers and Ni3P-like P centers. The locally ordered Ni centers and P centers are the nuclei sites, which can explain well the origin of initial nuclei to form the crystalline phases after high-temperature annealing. The starting temperature of high-temperature decomposition of ammonium perchlorate was found having a significant decrease in the presence of the noncrystalline Ni–P nanoparticles. Therefore, the as-prepared noncrystalline Ni–P nanoparticles can be used as a potential catalyst in the thermal decomposition of ammonium perchlorate.
