NOVELTY - A hydrogen gas producing apparatus comprises autothermal primary reactor having inlet adapted to receive a reactant stream comprising a hydrocarbon fuel, oxygen, and steam, and outlet to receive product gases, one of which being hydrogen; two reforming reaction zones; upstream reforming catalyst(s) comprising platinum and rhodium in the first reforming reaction zone; and downstream reforming catalyst(s) in the second reforming reaction zone.    USE - For producing hydrogen gas from fuel, useful for fuel cell system of vehicle (claimed).    ADVANTAGE - The reforming catalyst exhibits improved activity, and/or durability. It exhibits the ability to steam reform low concentrations of fuel and short chain hydrocarbons effectively.    DETAILED DESCRIPTION - A hydrogen gas producing apparatus comprises autothermal primary reactor having inlet adapted to receive a reactant stream comprising a hydrocarbon fuel, oxygen, and steam, and outlet to receive product gases, one of which is hydrogen; two reforming reaction zones, the first reaction zone having a light-off temperature proximate to the inlet, the second reforming reaction zone being proximate to the outlet; upstream reforming catalyst(s) comprising platinum and rhodium in the first reforming reaction zone, where a sufficient amount of platinum is present within the upstream reforming catalyst(s) to lower the first light-off temperature below that of a rhodium based reforming catalyst without an amount of platinum, and the upstream reforming catalyst(s) is selected to perform optimally in conjunction with operating conditions in the first reforming reaction zone; and downstream reforming catalyst(s) in the second reforming reaction zone. The operating conditions in the first reforming reaction zone have a temperature higher than the temperature of the second reforming reaction zone, and the downstream reforming catalyst(s) is selected to perform optimally in conjunction with operating conditions in the second reforming reaction zone.    DESCRIPTION OF DRAWING(S) - The figure is a schematic illustration of a fuel processing system and fuel cell stack.