Artificial photosynthesis is promising to convert solar energy and CO2into valuable chemicals, and to alleviate the problems of the greenhouse effect and the climate change crisis. Here, we fabricated a novel photocatalyst by directly growing Bi2MoO6nanosheets on three-dimensional (3D) N,O-doped carbon (NO-C). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show that the designed photocatalyst ensured the close contact between Bi2MoO6and NO-C, and reduced the stacking of the NO-C layers to provide abundant channels for the diffusion of CO2, while NO-C can allow for fast electron transfer. The charge transfer in this composite was determined to follow a step-scheme mechanism, which not only facilitates the separation of charge carriers but also retains a strong redox capability. Benefiting from this unique 3D structure and the synergistic effect, BMO/NO-C showed excellent performance in photocatalytic CO2reductions. The yields of the best BMO/NO-C catalysts for CH4and CO were 9.14 and 14.49 μmol g−1h−1, respectively. This work provides new insights into constructing step-scheme photocatalytic systems with the 3D nanostructures.