Formation of CoTe_2 embedded in nitrogen-doped carbon nanotubes-grafted polyhedrons with boosted electrocatalytic properties in dye-sensitized solar cells

摘要

Developing high active and earth-abundant electrocatalysts is a challenge for commercialization of dye-sensitized solar cells (DSSCs). Herein, a designed synthesis of CoTe2 nanoparticles embedded in nitrogen-doped carbon nanotubes-grafted polyhedron (CoTe2@NCNTs) using zeolitic imidazolate framework-67 (ZIF-67) as template is reported. Benefiting from the high surface area induced by the in situ growth of CNTs and the synergistic effect between CoTe2 and the N-doped nanostructured carbon, CoTe2@NCNTs hybrids exhibit remarkable catalytic activity toward the reduction of I-3(-) ions. When employed as counter electrode (CE) of DSSCs, CoTe2@NCNTs hybrids deliver overwhelming power conversion efficiency (PCE) of 9.02%, possessing similar to 12% improvement compared with the Pt CE (8.03%). This study provides an emerging substitute for traditional Pt CE and a strategy to synthesize efficient electrocatalysts via rational surface engineering.