One of the challenges concerning proton exchange membrane fuel cell (PEMFC) is how to control the air compressor voltage so that enough oxygen is provided for reaction, while the net power (the produced electrical power minus the air compressor used power) is maximized. Another challenge is the enhancement of the PEMFC lifespan by controlling the inlet hydrogen flow in a way that enough hydrogen is provided for reaction, and the pressure difference between cathode and anode is kept as small as possible. This paper presents a gradient-based extremum seeking control, which controls the inlet oxygen flow for net-power optimization of a PEMFC. High speed, simplicity, and online control decision are the advantages of this controller. Additionally, the paper presents a first order sliding mode controller for decreasing the pressure difference between gases at cathode and anode in order to enhance the PEMFC lifespan. Control law simplicity, not requiring a state observer, and chatter free response are the advantages of the sliding mode controller, which controls the inlet hydrogen flow. Both controllers are simulated on a sample PEMFC model simultaneously, and the results show that the partial pressure difference of oxygen and hydrogen is approximately zero, and at the same time the PEMFC net power is increased up to 17 percent.