Multiwalled carbon nanotubes confined Mo2C nanoparticles as counter electrodes for boosting triiodide reduction reaction in dye-sensitized solar cells

Multicomponent synergistic regulation has been an effective strategy to enhance the electrochemical properties of Mo 2 C-based counter electrode (CE) catalysts in dye-sensitized solar cells (DSSCs). Herein, Mo 2 C/CNTs composites (termed MCNT x , x  = 2, 4, 6, 8, means the phosphomolybdic acid (PMo 12 ) concentration) have been prepared using well-crystallized Mo 2 C nanograins anchored on the wall of multi-walled carbon nanotubes (CNTs) by a facial two-step approach. Through simple ultrasound assistance, PMo 12 was spontaneously connected with CNTs, and the obtained precursors can be converted to the target product MCNT x by a simple thermal decomposition at N 2 atmosphere. The modified CNTs guarantees the fast transfer of electrons and serves as framework for the support of Mo 2 C nanoparticles and mass diffusion, moreover the well-defined Mo 2 C nanoparticles ensures more accessible active sites to promote the triiodide reduction reaction (IRR). As a result of the synergistic effect between modified CNTs and Mo 2 C nanoparticles, MCNT x show excellent power conversion efficiency (PCE) when fabricated as CEs of DSSCs. The MCNT6-based DSSC exhibits a superior PCE up to 8.06 %, which is significantly higher than DSSC assembled with Pt CE (7.19 %).