Abstract: A fuel cell is provided, which includes a first plenum around an anode for receiving fuel, and a second plenum around a cathode for receiving oxygen. A fluid controller controls the supply of fuel to the first plenum or oxygen to the second plenum. A sensor detects the load on the fuel cell, and a controller controls the fluid controller in response to the load detected by the sensor. A method for controlling the output of a fuel cell is also provided, which includes the step of providing a fuel cell having a reaction area with an effective area where reactions may occur. The demand on the fuel cell is detected and the effective area of the reaction area is varied in response to the demand. Alternatively, the fuel cell may have an internal resistance, and the method may include varying the internal resistance in response to the demand.

Abstract: The composition of matter, vanadyl phosphite, useful as a precursor to a vanadium/phosphorous oxide oxidation catalyst used in the selective oxidation of n-butane to produce maleic anhydride.

Abstract: The invention relates to vanadium/phosphorus oxide catalyst precursors useful in preparing catalysts useful in the oxidation of hydrocarbons containing 4 carbon atoms to maleic anhydride.

Abstract: A vanadium/phosphorus oxide oxidation catalyst suitable for catalytic oxidation of C.sub.4 feed stock in the preparation of maleic anhydride is formed by calcining an intercalation complex of the formula VOHPO.sub.4 .multidot.0.5H.sub.2 O.multidot.({C.sub.n H.sub.2n+1 }--X).sub.z in which n has a value of from 0 to 20, z has a value of from about 1.5 to about 1.9; and X is an oxygen- or nitrogen-containing functional group operable to form hydrogen bonds with the structural P--OH and water groups of the complex.