Highly efficient and robust noble-metal free bifunctional water electrolysis catalyst achieved via complementary charge transfer

Abstract The operating principle of conventional water electrolysis using heterogenous catalysts has been primarily focused on the unidirectional charge transfer within the heterostructure. Herein, multidirectional charge transfer concept has been adopted within heterostructured catalysts to develop an efficient and robust bifunctional water electrolysis catalyst, which comprises perovskite oxides (La 0.5 Sr 0.5 CoO 3– δ , LSC) and potassium ion-bonded MoSe 2 (K-MoSe 2 ). The complementary charge transfer from LSC and K to MoSe 2 endows MoSe 2 with the electron-rich surface and increased electrical conductivity, which improves the hydrogen evolution reaction (HER) kinetics. Excellent oxygen evolution reaction (OER) kinetics of LSC/K-MoSe 2 is also achieved, surpassing that of the noble metal (IrO 2 ), attributed to the enhanced adsorption capability of surface-based oxygen intermediates of the heterostructure. Consequently, the water electrolysis efficiency of LSC/K-MoSe 2 exceeds the performance of the state-of-the-art Pt/C||IrO 2 couple. Furthermore, LSC/K-MoSe 2 exhibits remarkable chronopotentiometric stability over 2,500 h under a high current density of 100 mA cm −2 .