An apparatus to produce high purity hydrogen and electricity is disclosed in one embodiment of the invention as including a fuel cell configured to convert the chemical energy of a fuel to electricity and heat. An electrolyzer cell is placed in electrical and thermal communication with the fuel cell and is configured to electrolyze an oxygen-containing compound, such as steam or carbon dioxide, using the electricity and heat generated by the fuel cell. In selected embodiments, the fuel cell and electrolyzer cell are physically integrated into a single electrochemical cell stack.