Hydrogen-treated commercial WO3 as an efficient electrocatalyst for triiodide reduction in dye-sensitized solar cells.

The electrocatalytically inactive commercial WO3 can be transformed into an efficient counter electrode (CE) material for dye-sensitized solar cells (DSCs) via facile hydrogen treatment. The energy conversion efficiency of the DSCs with the hydrogen-treated WO3 CE was 5.43%, while the corresponding value for commercial WO3 with the stoichiometric surface was only 0.63%.