▎ 摘　　要

The transition metal oxide Nb2O5 has advantages and potential in electrochemical catalysis. However, routine Nb2O5 catalyst has large bulk resistance and poor conductivity. In this study, the Nb2O5 crystal lattice@graphene oxide (Nb2O5-CL@GO) composite is prepared. The lattice atoms effectively couple to the GO atoms because of few atom layers in Nb2O5-CL@GO. Face-type coupling (FTC) is formed between the crystal-lattices face and GO face, which is benefited to increase the electron-coupling area, to increase the synergistic effect. In thick Nb2O5 layer@GO (Nb2O5-TL@GO), only edge atoms in the thick Nb2O5 layer are directly electron coupled with the GO, while the surface atoms on the thick Nb2O5 have weak electronic coupling to GO. Therefore, line-type-coupling (LTC) in Nb2O5-TL@GO reduce exposure of electron-coupling area. Compared with Nb2O5-TL@GO, Nb2O5-CL@GO exhibited excellent electrocatalytic activity and metallic properties in the electrolyte. In addition, the performance of Nb2O5-CL@GO composite as an electrocatalytic electrode in dye-sensitized solar cells is superior to that of the noble Pt. The power conversion efficiency (PCE) is 10.81% under 1-sun illumination (AM 1.5 G, 100 mW cm(-2)). Compared with Si solar cells, DSCs based on Nb2O5-CL@GO composite is suitable for use in low illumination intensity and radiation angle. Finally, the DSCs based Nb2O5-CL@GO composite has good stability. The results are of great interest in the materials and interface science, electrocatalysts, and energy conversion.