Patent ID: 8529799
Filing Date: 2013-09-10
Classification: C01G,C01P

Abstract:
1. A manufacturing method of a metal oxide semiconductor material for gas sensors wherein a change in resistance of the metal oxide semiconductor material is caused by gas absorption, the method comprising: a precursor solution synthesis step of synthesizing an oxide precursor solution in which an oxide precursor is dispersed by dropping a metal-salt aqueous solution into an alkaline aqueous solution while stirring the alkaline aqueous solution; a pH adjustment step of adjusting the pH of the oxide precursor solution by adding a polar solvent to the oxide precursor solution so as to lower the pH of the oxide precursor solution; a precursor-colloid dispersion preparation step of preparing an oxide precursor-noble metal colloid dispersion in which the oxide precursor and a noble metal colloid are dispersed substantially uniformly by adding a noble metal colloid solution in which the noble metal colloid is dispersed to the oxide precursor solution whose pH has been adjusted; a purifying step of purifying the oxide precursor-noble metal colloid dispersion with a polar solvent added thereto to prepare a purified oxide precursor-noble metal colloid dispersion from which impurities have been removed; and a freeze-drying step of freeze-drying a precipitate of the purified oxide precursor-noble metal colloid dispersion.