NOVELTY - A fuel cell is operated by regenerating cell by providing a hydrogen containing fuel to an anode while operating the cell to reduce the cathode potential to below 0.66 V, and maintaining the cathode potential below the 0.66 V for a second period of time to restore at least a major portion of the cell performance.    USE - For operating fuel cell for automotive applications.    ADVANTAGE - The invention can maintain high performance level of the cell for an extended period of time.    DETAILED DESCRIPTION - Operation of a fuel cell involves providing a hydrogen containing fuel to the anode and an oxygen containing oxidant to the cathode to generate, for a first period of time, an electric current within the external circuit for operating the primary electricity using device, the cell operating conditions being selected such that, during the course of the first period of time, the cathode potential is maintained above 0.66 V and cell performance decreases. The cell is regenerated by providing a hydrogen containing fuel to the anode while operating the cell using procedures to reduce the cathode potential to below 0.66 V, and maintaining the cathode potential below the 0.66 V for a second period of time to restore at least a major portion of the cell performance. The steps are repeated to reduce the decrease in cell performance over time.    An INDEPENDENT CLAIM is also included for a fuel cell system comprising a fuel cell including a proton exchange membrane (PEM) as the electrolyte, an anode electrode disposed on one side of the membrane, and a cathode electrode disposed on the other side of the membrane; an external electric circuit connecting the anode and cathode electrodes; a primary electricity-using device connected to the external circuit; and mechanism for providing a hydrogen containing fuel to the anode electrode and for providing an oxidant to the cathode electrode. The anode and cathode electrodes are both comprise a platinum containing catalyst. The fuel cell system is constructed and arranged, and includes controller for maintaining the potential of the cathode electrode.