Synergistic NiO/Fe2O3 Heterostructure-Enhanced Electrocatalytic Performance in Dye-Sensitized Solar Cells

Dye-sensitized solar cells (DSSCs) can efficiently convert solar energy into electricity, which is considered a promising approach to reduce the dependence on fossil resources. However, the development of counter electrodes (CEs) has been limited. Hence, the search for efficient earth-abundant CE materials is highly desired. Herein, an improved simple synthesis method is reported for the deep optimization of electrode activity by coupling the N-defect carbon with the NiO/Fe2O3 heterojunction (denoted as NiO/Fe2O3@NC). The carbon layers with large specific surface area and high conductivity as bridging transporters not only can maintain structural stability but full exposure to active sites. Moreover, the synergetic effect of NiO and Fe2O3 can promote I-3(-) reduction reaction and suppress iodide ion coupling simultaneously. The obtained NiO/Fe2O3@NC serves as CEs. Compared with the unsupported NiO@NC, the Fe2O3@NC composites displayed superior electrochemical properties. Meanwhile, the power conversion efficiency (PCE) of DSSC with NiO/Fe2O3@NC CE attained 8.69%, exceeding that with NiO@NC (6.51%), Fe2O3@NC (6.22%), and commercial Pt CEs (7.52%). This study would contribute to the construction and development of excellent electrocatalysts for other important reactions.