▎ 摘　　要

Dye-sensitized solar cells (DSSCs) are expected to be a powerful competitor of conventional silicon devices due to their simple, low-cost, and pollution-free processing. Platinum (Pt) as commonly used counter electrode (CE) material is, however, limited to its expensive cost and undesired reverses. The development of an efficient Pt-free CE material with high electrical conductivity and excellent electrocatalytic activity is a feasible strategy to solve the above limitations. Herein, we have proposed a simple two-step strategy to synthesize hierarchical Co3O4/graphene oxide composite catalysts. The as-prepared nanoporous Co3O4 cubes with hierarchical architecture may provide a mass of electrocatalytic activity sites. The combination of hierarchical structures and graphene oxide may enable the electrons to rapidly transfer on the submicron-sized graphene oxide. As a novel and low-cost CE material, DSSCs based on hierarchical Co3O4/graphene oxide composite exhibit photovoltaic performance comparable to the traditional Pt CE. This is due to the ideal combination of excellent electrocatalytic activity and high conductivity. Our finding provides a judicious strategy for nanoscale synthesis of hierarchical composites and may facilitate the preparation of efficient and low-cost CE materials for DSSCs.