Inorganic membrane reactors combine reaction and separation operations in a single unit. Preferential permeation of a product species through the membrane enhances equilibrium-limited reactions beyond the thermodynamic limit. Proper catalyst formulation and spatial distribution also enhance membrane reactor performance. To minimize reactant loss due to high gas permeation the thickness of the gamma-alumina layer in a composite alumina membrane (Membralox) was increased to 17 mu m by slip-casting with alumina sol. Among the catalysts investigated a formulation of 1.10 wt. % Pt and 1.36 wt. % Sn supported on gamma-alumina pellets yielded the highest activity selectivity and stability for the dehydrogenation of ethane to ethylene. Using this catalyst composition, various nonuniform platinum distributions within the pellets were prepared by solution impregnation, while maintaining a uniform distribution of Sn. The effect of nonuniform catalyst distribution on dehydrogenation of ethane in a packed-bed membrane reactor (PBMR) under well-mixed, isothermal conditions was evaluated both experimentally and theoretically. Reactor performance is maximized when the catalyst is concentrated near the surface of the support. Supraequilibrium conversions, about 80% beyond equilibrium values, were obtained with the narrow surface-step catalyst pellets. Experimental results agree well with theoretical predictions, obtained without the use of any adjustable parameters. The effect of membrane thickness on reactor performance was also investigated by comparing the 17-mu m alumina membrane with a 1.2-mm-thick porous Vycor glass, using pellets with the narrow surface-step distribution. For the experimental conditions employed, relatively low permeation through the porous Vycor resulted in conversions near fired-bed reactor values.