Cellular　metals　with　a　large　surface-to-volume　ratio　and　excellent　electrical　conductivity　have　attracted　great　attention　due　to　their　wide　application.　However,　the　existing　processes　for　fabrication　of　cellular　metallic　structures　are　generally　complex　and　dependent　on　the　sacrificial　materials　or　templates,　and　therefore,　it　is　highly　desirable　to　develop　a　facile　process.　Herein,　we　propose　a　novel　gas-assisted　reconstruction　strategy　for　in　situ　fabrication　of　micron-porous　architectures　on　Ag　precursor　metal　using　a　CH4/O2　gas　mixture　at　750　°C.　The　obtained　results　indicate　that　large-area　and　clean,　porous　Ag　architectures　are　successfully　created　through　the　treatment　in　CH4/O2　gas.　The　formation　of　cellular　structure　is　mainly　due　to　the　simultaneous　diffusion　of　H2,　CO　and　O2　into　Ag　bulk　and　fast　reaction　at　elevated　temperatures.　The　process　is　clean　and　applicable　to　creation　of　porous　architectures　(from　surface　texturing　to　3-D　cellular　structure)　on　Ag　metal,　avoiding　the　use　of　sacrificial　materials　or　templates.　Furthermore,　we　have　demonstrated　that　the　formed　micron-porous　Ag　sheet　with　large　effective　area,　high　electrical　conductivity　can　be　directly　used　as　a　free-standing　electrode　for　electrochemical　supercapacitors　with　a　high　capacitance.　©　2018　Elsevier　Ltd