Non-Pt counter electrode catalysts using tantalum oxide for low-cost dye-sensitized solar cells

► Tantalum oxide and tantalum pentoxide were synthesized using a simple and facile chemical route. ► Tantalum oxide and tantalum pentoxide as catalysts were firstly tested for use in the DSC system. ► Tantalum oxide as a CE in DSCs shows a highly Pt-like electrocatalytic activity. ► TaO-DSC shows a higher PCE (6.48%), reaching 90.5% of the level obtained using Pt as a CE (7.16%). ► Tantalum oxide has great potential for substitution of Pt in DSCs while providing comparable performance.