Edge/Defect-rich, Metallic, and Oxygen-heteroatom-doped WS2 Superstructure with Superior Electrocatalytic Performance for Green Solar Energy Conversion

摘要： Two-dimensional tungsten sulfide is widely applied in electrocatalysis field. However, WS2 possesses catalytic active sites located at the layer edge and an inert surface for catalysis. Therefore, increasing the exposure of active sites at the edge and effectively activating the inert sites on the surface is important challenges. Here, we synthesize edge/defect-rich and oxygen-heteroatom-doped WS2 (ED-O-WS2) superstructure. The power-conversion efficiency (PCE) of dye-sensitized solar cells (DSCs) based on ED-O-WS2 counter electrode reach 10.36% (under 1 Sun, AM 1.5, 100 mW cm?2) and 11.19% (under 40 mW cm?2). These values are, to our knowledge, the highest reported efficiency for DSCs based on Pt-free counter electrodes in I3-/I- electrolytes. Analysis of micro-nano structure and electrocatalytic mechanism indicate that ED-O-WS2 exhibit metallic properties in the electrolyte, and that rich edge/defect and oxygen doping in ED-O-WS2 play an important role in improving the catalytic activity of WS2. Moreover, ED-O-WS2 displays better catalytic reversibility for I3-/I- electrolytes than that of noble metal Pt.