The influence of conditions of heat treatment of a solution [Zn(H2O)(O2C5H7)(2)] in 1-butanol (temperature 125-185 degrees C, treatment times 2, 4, and 6 h) on dispersion and microstructure of the formed nanocrystalline and poorly aggregated zinc oxide, promising component for optoelectronics, including as receptor materials of chemical gas sensors, was investigated. IR spectroscopy showed that the precursor decomposition occurs through the cleavage of the C-C bond of the ligand to form acetone and butyl acetate. It was determined that at the minimum treatment temperature and time (125 degrees C, 2 h) ZnO nanoparticles are nearly spherical, and under hard conditions, rodlike particles are formed. At 125 degrees C (treatment times 4 and 6 h), rodlike particles are organized into dense agglomerates resembling bundles in shape, and at the higher temperatures there is no aggregation of ZnO nanoparticles. The high CO selectivity and sensitivity (4-100 ppm) was revealed for oxide coatings obtained by screen printing using ZnO nanopowders synthesized at 125 degrees C (treatment times 2 and 4 h).