Pure　and　Cobalt　doped　ZnO　microstructures　have　been　prepared　by　hydrothermal　method　and　calcinations　at　600　°C.　The　crystal　structure,　surface　morphology　and　chemical　composition　of　the　samples　were　determined　by　X-ray　diffraction,　scanning　electron　microscopy　and　X-ray　photoelectron　spectroscopy,　respectively,　indicating　that　the　presence　of　a　small　quantity　of　Co　ions　can　greatly　affect　the　morphology　of　the　ZnO　nanostructures.　When　used　for　methane　gas　sensing,　1　wt%　Co/ZnO　(CZ1)　sensor　exhibited　the　highest　response　to　100　ppm　methane　at　140　°C,　which　were　about　2　times　higher　than　that　of　pure　ZnO　samples.　Moreover,　the　1　wt%　Co/ZnO　sensor　also　displayed　fast　response/recovery　time　(19/27　s),　low　detection　limit　(50　ppb).　Thus,　the　CZ1　microstructures　are　promising　for　practical　methane　sensing　applications.　©　2015　Elsevier　B.V.　All　rights　reserved.　All　rights　reserved.