NOVELTY - Preparation of a steam reforming catalyst composition involves applying a coating composition comprising an alumina precursor onto a substrate to form a coated substrate; providing an alumina stabilizer; drying the coated substrate to form a dried support; and hydrothermally pre-aging the dried support in a gas atmosphere comprising water to form hydrothermally stabilized support.    USE - For the preparation of steam reforming catalyst composition; in methane steam reforming (claimed); form making hydrogen; for supplying hydrogen for fuel cells.    ADVANTAGE - The method provides superior results and properties e.g. the coated catalyst was demonstrated to be highly stable under steam reforming conditions (high temperature and high pressure of steam). The method provides high performance and stability under the hydrothermal conditions that are typical of steam reforming. The method provides good stability and conversion or selectivity. The method provides preparation of highly stable suspended catalyst particles in liquid medium, modification of the liquid suspension properties to achieve an adherent, uniform coating on a reactor wall or on catalyst substrates such as felts, foams, ceramics and metal flat surfaces and coating methods to achieve uniform catalyst coatings with excellent adhesion to a substrate in short catalyst preparation time (e.g. in dip coating, reduced dips); improved catalyst performance, high stability under steam reforming conditions (steam, high temperature and high pressure), high conversions at relatively short contact times, selectivity control, lower cost, ease of manufacturing, and low temperature operation.    DETAILED DESCRIPTION - Preparation (M1) of a steam reforming catalyst composition involves applying a coating composition comprising an alumina precursor onto a substrate to form a coated substrate; providing an alumina stabilizer; drying the coated substrate to form a dried support; and hydrothermally pre-aging the dried support in a gas atmosphere comprising water (at least 1 atm) (partial pressure) and at least 850degreesC to form hydrothermally stabilized support.    INDEPENDENT CLAIMS are included for the following:    (1) a method (M2) of methane steam reforming involving: conducting a reaction in which methane and steam contact a catalyst at at least 800degreesC for at least 1000 hours (without regenerating the catalyst). The catalyst comprises a stabilized alumina support and a catalytically active material. The process conditions includes: a) a contact time of at most 15 minutes while achieving an average approach to equilibrium conversion of greater than 80%; b) a contact time of at most 10 minutes while achieving an average approach to equilibrium conversion of greater than 70%; or c) a contact time of at most 5 minutes while achieving an average approach to equilibrium conversion of greater than 65%; and    (2) a method (M3) of methane steam reforming involving: passing a stream comprising methane and water in a steam to carbon ratio of at most 3; and contacting a catalyst at a contact time of at most 10 minutes and maintaining the same conditions for at least 1000 hours. There is a continuous period of at least 500 hours in which the methane conversion changes by at most 3%. At least 2 mol of methane are converted per gram catalytically-active material each minute.