Shape-controlled synthesis of porous fibrous cobalt powders

The fibrous precursor can be obtained by coordination precipitation process, using oxalate, cobalt chloride and ammonia. The composition and morphology of fibrous precursor were characterized by XRD, IR, DTA/TGA and SEM analysis. The results show that XRD pattern and composition of the precursor with fibrous morphology precipitated at pH=9.0 were different from that Of beta-CoC(2)O(4)center dot 2H(2)O precipitated at pH=1.0. The mechanism on the thermal decomposition of fibrous precursor was addressed. The influences of various conditions in pyrolysis, including the temperature, time, atmosphere, and the morphology of the precursor, on the morphology, average size and specific surface area of the Co powders were investigated in detailed. At last, the final product, fibrous cobalt powders with diameter about 0.3 similar to 0.5 mu m in size and 40 similar to 60 in aspect ratio, were produced by thermal decomposition at 400 similar to 500 degrees C in the weak reducing atmosphere. The structure of pores in cobalt powders was capillary tube with open ports and the majority was mesoporous.