Abstract: A new photocatalyst, which is high in visible light response, is great in quantum efficiency, and is more excellent in photocatalytic activity, is provided. A composite metal oxide, prepared combining two photocatalytic systems of TiO2 and BiVO4, including elements of Bi, Ti, and Vi as composition elements, can be a photocatalyst having a high activity under visible light. Particularly, BiTiVO6, which is obtained at a compounding ratio of 1:1, can be a photocatalyst having a remarkably high activity under visible light. Moreover, a composite metal oxide expressed by a general formula BiTiMO6 (in the formula, M represents at least one element selected from a group consisting of V, Nb, and Ta) can be a photocatalyst having a high activity under visible light.

Abstract: An electrochemical deposition method in which the structure of a substance to be deposited on the surface of a working electrode is determined, an electrochemical deposition apparatus, and a microstructure are provided. A positive electrode 1 and a negative electrode 2 functioning as a working electrode are arranged oppositely in a liquid tank 5 containing an electrolytic (acid) solution (hereinafter referred to as “solution”) 4 in which plural substance are dissolved in an ionic state, and then a predetermined voltage is applied between the positive electrode 1 and the negative electrode 2. A reference electrode 3 is also arranged in the liquid tank 5 and the potential between the negative electrode 2 and the reference electrode 3 is measured. Since the solution 4 can be considered as a conductor, the potential V1 of the negative electrode 2 relative to the solution 4 can be determined.