Economically viable V2O3@activated carbon composite materials as counter electrodes for dye sensitized solar cells by single step reduction

V2O3@activated carbon (V2O3@C) composite catalysts with different mass ratios have successfully been fabricated using a facile one-step the reduction of ammonium vanadate (NH4VO3) with AC in a high-temperature solid-state reaction. V2O3@C composites were further served as catalytic materials for counter electrodes (CEs) in encapsulation of dye sensitized solar cells (DSSCs). The morphology and microstructure of each V2O3@C composite were determined by scanning electron microscopy and X-ray diffraction. Cyclic voltammetry studies revealed that the V2O3@C composites showed a higher electrocatalytic activity than AC and V2O3 for the reduction of triiodide ions. Electrochemical impedance spectroscopy and Tafel analysis data for the symmetrical cells indicated a lower charge transfer resistance and higher exchange current density for V2O3@C composite than AC and V2O3. The experimental results showed that power conversion efficiencies (PCE) of 4.94, 5.55 and 5.32% were obtained for AC:NH4VO3 mass ratios of 1:3, 2:3 and 4:3 as counter electrode toward the reduction of I3−/I− ions respectively, which were superior to higher than that of AC (2.10%) and V2O3 (3.33%) electrode under the same conditions. The enhanced electrode performance can be ascribed to the combined effects of the relatively larger surface area and higher conductivity of V2O3@C composite catalysts.