Dual sites of CoO nanoparticles and Co-Nx embedded within coal-based support toward advanced triiodide reduction

Herein, coal-based composites embedded with CoO nanoparticles and Co-Nx dual sites are constructed and used for triiodide reduction in a dye-sensitized solar cell. Concentrated hydrochloric acid is firstly provided to pretreat coal so as to eliminate interference from other metal impurities. The ash-rich coal with addition of cobalt phthalocyanine and pyrolysed at 800 ℃ (denoted as Coal-10 wt% CoPc-800) as counter electrode shows a much enhanced activity for triiodide reduction reaction with the power conversion efficiency of 8.32%, which is better than that of Coal-800 counter electrode (7.83%), and also exceed that of Pt counterpart (8.02%), revealing the generated Co-Nx and CoO nanoparticles sites derived from CoPc can synergistically boost the electrochemical activity. In particular, a significantly enhanced electrochemical performance is achieved after introducing an additional 33 wt% TiO2 binder into the above mentioned Coal-10 wt% CoPc-800 (denoted as Coal-10 wt% CoPc-800-33 wt% TiO2). The binding ...