▎ 摘　　要

MnO2 nanotubes were synthesized via hydrothermal conditions. We investigated their catalytic activities with a counter electrode (CE) in DSSCs by photocurrent-voltage (J-V) curves and measured conversion efficiency. To enhance their power conversion efficiency (PCE), different amounts of reduced graphene were added by simple physical mixing. With the addition of 6 wt% reduced graphene (rGO), the short-circuit current density, open-circuit voltage, and fill factor (FF) were J(sc) = 15.97 mA, V-oc = 0.71 V, and FF = 0.51. Furthermore, the conversion efficiency achieved 5.77%, which was slightly better than the commercial Pt CE (PCE = 5.40%). Compared to the traditional Pt CE of DSSCs, this material has the advantages of low cost, simple synthesis, and high conversion efficiency with graphene assistance.