Synergistic coupling of heterointerface Ni2P/Co2P nanocrystals anchored on MXene nanosheets for high-performance oxygen and hydrogen evolution reactions

Abstract

The kinetic energy barrier (E_a), which significantly decreases in the intermediate transition state of adsorption, can be modulated by designed heterointerface catalysts. The intrinsic activity can be tuned to a typical multicomponent nature. Moreover, the sheet-like structures and honeycomb voids provide abundant active sites, an advantage for ion penetration and gas production. However, a significant concern is that water splitting into hydrogen and oxygen remains challenging due to a lack of stability, poor performance, and scarcity of metals. Herein, we report that a delaminated Ti₃C₂ MXene acts as a substrate, synergistically interacting with a bimetallic Ni₂P/Co₂P heterostructure. As expected, the prepared Ni₂P/Co₂P_8@Ti₃C₂ nanoporous material exhibits good performance toward OER and HER activity. It requires only 255 and 82 mV to reach 10 mA cm⁻² current density with a slight Tafel slope of 61 and 89 mV dec⁻¹ for the OER and HER, respectively, in 1.0 M KOH electrolyte. Furthermore, the Ni₂P/Co₂P_8@Ti₃C₂ electrocatalyst shows superior stability over 60 h when applied at a constant potential of 1.50 V and −1.10 V vs. a RHE. Of interest, this work demonstrated the design of a heterointerface nanoporous material with ultrathin 2D MXene nanosheets to achieve state-of-the-art activity for practical applications and next-generation energy materials.