| abstract |
Disclosed is a visible light response-type photocatalyst powder of which the capability of decomposing an organic gas responds nonlinearly to a light exposure under visible light in an illuminance range of not less than 200 lx and not more than 2500 lx. The visible light response-type photocatalyst powder has a gas decomposition rate of not less than 20%, for example, when visible light, which has only a wavelength of not less than 380 nm and an illuminance of 2500 lx, is applied. The gas decomposition rate (%) is defined by formula: (A - B)/A OE100 wherein A represents a gasconcentration before light irradiation and B represents a gas concentration when not less than 15 min has elapsed from the light irradiation and, at the same time, the gas concentration is stable. The gas concentrations are measured while allowing an acetaldehyde gas having an initial concentration of 10 ppm to flow into a flow-type apparatus in which 0.2 g of a sample is placed. |