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 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.