NOVELTY - A supported catalyst comprises at least one alkaline-earth metal hexaaluminate support ( greater than or equal to 95 vol.%) and at least one element selected from iridium (Ir), palladium (Pd) and platinum (Pt), where the elements are dispersed on the support and the catalyst support has a surface area of greater than or equal to 6 m2/g.    USE - As supported catalyst (claimed) in steam reforming processes; and in the production of hydrogen from fuel sources (such as natural gas, liquefied petroleum gas, alcohols, naphtha and other hydrocarbon fuel containing methane, ethane, propane or butane), which is useful in the metals processing industry, in semiconductor manufacturing, in petroleum desulfurization, in power generation via electrochemical cells and combustion engines and as feedstock in ammonia synthesis and other chemical processes.    ADVANTAGE - The catalyst support has a surface area of greater than or equal to 6 (preferably greater than or equal to 12, especially greater than or equal to 18) m2/g. The catalyst exhibits improved activity, stability in both air and reducing atmosphere and sulfur tolerance. The catalyst support do not require binders and can be single phase materials. The catalyst is tolerant of reduction-oxidation cycles. The stability of the support in both air and reducing atmospheres allows the active metal on the support to remain dispersed during hydrocarbon reforming. Hence the catalyst retains its catalytic activity significantly longer than conventional catalysts. The catalyst is capable of operating in a hydrocarbon fuel feed containing greater than or equal to 1 ppm by mass (preferably greater than or equal to 10 ppm by mass, especially greater than or equal to 100 ppm by mass) of sulfur; is insensitive to the presence of O2 in the feed and is capable of operating in a hydrocarbon fuel feed containing greater than or equal to 1 ppm by mass of oxygen atoms other than the oxygen atoms in steam. The catalyst is capable of operating in a hydrocarbon fuel active feed containing greater than or equal to 100 ppm by mass of O2. The catalyst provides stable performance over extended periods of time upon exposure to both air and reducing atmosphere. The catalyst support allows generation of H2 by hydrocarbon steam reforming using feed streams contaminated with more sulfur and oxygen than is conventionally feasible. The stability of the support in both air and reducing atmospheres allows the active metal on the support to remain dispersed during hydrocarbon reforming. As a result the catalyst retains its catalytic activity longer than conventional catalysts. The addition of small amounts of Ir, Pt and/or Pd to conventional catalysts containing nickel (Ni), cobalt (Co) or ruthenium (Ru), reduces reaction initiation temperatures in the presence of at least one feedstock impurity and facilitates catalyst regeneration after poisoning by sulfiding, coking or oxidation. The system incorporating the supported catalyst is capable of quicker and simpler startup from a cold or idle condition than system incorporating conventional catalysts. The catalyst can be shut down from operation and restarted without the use of reducing or inert gas. The process carried out using the supported catalyst reduces reformer system cost relative to conventional systems by eliminating components; and also improves safety and durability by reducing the number of interconnections, which can develop leaks in service.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of the supported catalyst involving: heating at least one precursor oxide in an atmosphere having a partial pressure of oxygen (O2) of less than or equal to 0.20 atm and containing at least 50 vol.% of at least one selected from H2, H2O and an inert gas; and producing the catalyst support.