To enhance the performance of a photocatalyst using a binder enough to uniformly carry the photocatalyst on activated carbon, to improve the contact of the photocatalyst with contaminated air and to effectively remove contaminants.

In the method for working a photocatalyst, a water-soluble binder such as polyvinyl alcohol or carboxymethyl cellulose is dissolved in water, titanium dioxide is dispersed in the resulting aqueous solution and this solution is impregnated into an adsorbent such as activated carbon. Water is then removed by drying and the titanium dioxide is carried on the adsorbent. The amounts of the binder and the titanium dioxide are 0.1 wt.% and 5 wt.%, respectively, based on the amount of the adsorbent.