Porous N-doped-carbon coated CoSe₂ anchored on carbon cloth as 3D photocathode for dye-sensitized solar cell with efficiency and stability outperforming Pt

Photocathode with superior catalytic activity, long-term stability, and fast mass/electron transfer is highly desirable but challenging for dye-sensitized solar cell (DSC). Herein, the ZIF-67 grown on carbon cloth is successfully transformed into CoSe₂ embedded in N-doped carbon nanocage (CoSe₂/N-C) via a growth-carbonization-selenization process. The carbon cloth supported CoSe₂/N-C, as photocathode of DSC, demonstrates a good long-term stability and high photovoltaic efficiency (8.40%), outperforming Pt. The good efficiency can be attributed to the high catalytic activity of CoSe₂, fast mass transfer of porous three-dimensional (3D) structure, and good electron transport derived from the intimate contact between CoSe₂ and highly conductive carbon cloth. The high stability would be ascribed to N-doped carbon coating that perfectly prevents CoSe₂ from decomposition. This work will pave the way to develop highly efficient and stable Pt-free photocathode for DSC.