Selective Surface Reconstruction of a Defective Iridium-Based Catalyst for High-Efficiency Water Splitting

Development of robust catalysts for electrochemical water splitting is a critical topic for the energy conversion field. Herein, a precise electrochemical reconstruction of IrTe(2)hollow nanoshuttles (HNSs) is performed for oxygen and hydrogen evolution reactions (OER and HER), the two half reactions of water splitting. It is determined that the reconstruction of IrTe(2)HNSs can be regulated by adjusting the potential during electrochemical dealloying, in which mild and high potentials lead to the formation of IrTe(2)HNSs with metal Ir shell (D-IrTe(2)HNSs) and IrO(x)surface (DO-IrTe(2)HNSs), respectively. Detailed analyses reveal that such electrochemical reconstruction has produced abundant defects in D-IrTe(2)and DO-IrTe(2)HNSs. As a result of this, D-IrTe(2)HNSs present a very low HER overpotential of 54 mV at a current density of 10 mA cm(-2)in 1.0mKOH. Moreover, the turnover frequency of DO-IrTe(2)HNSs is 0.36 O(2)s(-1)at an OER overpotential of 250 mV in 0.5mH(2)SO(4), outperforming the most of reported Ir-based catalysts. Furthermore, the D-IrTe2||DO-IrTe(2)couple exhibits promising activity for the overall water splitting in both 1.0mKOH and 0.5mH(2)SO(4). This study promotes the fundamental research for the design of efficient catalysts via surface engineering.