Novel coal-based carbon/CNTs composite counter electrode for highly efficient ZnO-based dye-sensitized solar cells
An interesting subject of non-fuel utilization of coal is the synthesis of high-performance coal-based carbon (CBC) materials to replace expensive Pt counter electrodes (CEs) in dye-sensitized solar cells (DSSCs). Selection of coal source, treatment, and structural optimization of coal should be considered to obtain high-performance CBC CEs. In this study, a coal-based porous carbon material with low cost and high performance was synthesized from three kinds of pulverized coal (collected from different regions of Xinjiang, China) through chemical activation followed by acid washing oxidation treatment. The prepared porous CBC material exhibited higher catalytic activity for the reduction of I−/I3− than Pt. The use of carbon nanotubes (CNTs) plus prepared porous CBC/CNTs composite materials as CEs for DSSCs led to a VOC of 0.62 V, a JSC of 21.92 mA cm−2, an FF of 0.42, and a conversion efficiency of 5.75%, which is higher than those of CEs made of porous CBC, CNTs, or Pt. The improvement in the conversion efficiency could be attributed to the synergistic effect of the good catalytic activity of the prepared CBC materials and the good conductivity of CNTs. Moreover, the double-layer structure played an important role in improving the adhesion and electron transport capacity. Results provide a theoretical basis for the possible use of cheap CBCs as CEs for thin-film solar cells. We use the ZnO as photoanode; the dye is N719.
KeywordsCoal-based carbon Counter electrode Higher electrocatalytic activity Composite structure
This research was financially supported by Xinjiang Uygur Autonomous Region Natural Science Foundation of China (No. 2017D01C023).
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