The positive electrode catalyst, and equipment

Cathode catalysts can be reduced reaction overvoltage at the positive electrode, and to provide equipment. Cathode catalyst of the present invention contains a layered metal oxide. The device of the present invention includes a positive electrode and the negative electrode, the positive electrode is formed by using the cathode catalysts containing layered metal oxide. Layered metal oxide is preferably a Ruddlesden-Popper type layered perovskite.