Using a high-speed and low-cost papermaking technology combined with subsequent sintering process, sinter-locked three-dimensional microfibrous networks consisting of; 2 vol % of 6-mm-diameter SS-316 microfibers were utilized to entrap; 25 vol % of 100-200-mm-diameter porous Al2O3 support particulates. Nickel, a most active component for ammonia decomposition, was then dispersed onto the pore surface of the entrapped Al2O3 support particulates by incipient wetness impregnation method. The resulting microfibrous catalysts took advantage of large void volume, entirely open structure, high heat/mass transfer, good thermal stability, and unique form factors, thereby leading to good activity for ammonia decomposition and significant reduction of overall bed weight and volume. This composite bed reactor was capable of producing 215 sccm hydrogen over per cm3 bed volume with ammonia conversion of 99.5% at 6508C.