Catalytic　combustion　of　methane　is　widely　used　in　industrial　and　transportation　activities.　The　commonly　used　Pd-based　catalysts,　however,　are　easily　deactivated　under　hydrothermal　conditions.　In　this　work,　we　adopted　a　novel　strategy　to　prepare　a　GaOx-doped　Pd/Al2O3　catalyst　via　the　oxidative　transformation　of　intermetallic　Pd5Ga3　nanocrystals　supported　on　gamma-Al2O3.　We　observed　a　synergistic　effect　between　palladium　and　gallium　oxide　via　formation　of　a　bi-functional　active　Pd-O-Ga　phase,　resulting　in　a　highly　active　and　exceptionally　stable　catalyst　that　could　markedly　suppress　the　sintering　of　noble　metals　under　harsh　conditions　(hydrothermal　treatment　at　750　degrees　C).　Moreover,　the　presence　of　a　large　amount　of　surface　oxygen　vacancies　and　the　surface　Pd-O-Ga　phase　could　promote　methane　combustion　over　the　catalysts.　It　is　believed　that　such　a　novel　dual-metal　catalyst　is　promising　in　practical　applications　for　methane　combustion.