Ternary　nickel　cobalt　selenide　(Ni-Co-Se)　alloy　based　hollow　microspheres　have　been　successfully　synthesized　via　a　simple　one-step　hydrothermal　route　by　controlling　different　hydrothermal　temperatures.　The　prepared　samples　were　divided　by　reaction　temperatures　(140,　160,　180　and　200 °C)　and　named　as　Ni-Co-Se-140,　Ni-Co-Se-160,　Ni-Co-Se-180　and　Ni-Co-Se-200,　respectively.　With　the　temperature　increasing,　the　hollow　microspheres　formed　at　the　lower　temperature　and　broke　at　the　higher　temperature,　and　the　sample　Ni-Co-Se-180　exhibited　the　most　regular　and　homogeneous　hollow　microspheres　with　a　size　of　1.5–2.5 μm.　Moreover,　the　Ni　atomic　ratios　in　Ni-Co-Se　alloys　increased　with　the　temperature　rising.　The　prepared　Ni-Co-Se　alloys　were　used　as　counter　electrode　(CE)　catalysts　for　dye-sensitized　solar　cells　(DSSCs).　A　series　of　electrochemical　tests　all　verified　Ni-Co-Se　alloy　based　CEs　had　superior　electrocatalytic　activities　and　Ni-Co-Se-180　CE　displayed　the　largest　current　density,　lowest　overpotential　and　smallest　charge-transfer　resistance　than　the　other　CEs　and　Pt　CEs.　Benefiting　from　their　unique　morphologies　and　surface　structures,　the　cells　with　the　Ni-Co-Se-160,　Ni-Co-Se-180　and　Ni-Co-Se-200　based　CEs　achieved　high　efficiencies　of　8.39%,　9.04%　and　8.72%,　respectively,　which　were　all　higher　than　that　of　Pt　CE　(8.07%).　©　2017　Elsevier　B.V.