Self‐Assemble and In Situ Formation of Ni₁₋<i>_x</i>Fe<i>_x</i>PS₃ Nanomosaic‐Decorated MXene Hybrids for Overall Water Splitting

Abstract

Abstract Herein, the authors present the development of novel 0D–2D nanohybrids consisting of a nickel‐based bimetal phosphorus trisulfide (Ni 1− x Fe x PS 3 ) nanomosaic that decorates on the surface of MXene nanosheets (denoted as NFPS@MXene). The nanohybrids are obtained through a facile self‐assemble process of transition metal layered double hydroxide (TMLDH) on MXene surface; followed by a low temperature in situ solid‐state reaction step. By tuning the Ni:Fe ratio, the as‐synthesized NFPS@MXene nanohybrids exhibit excellent activities when tested as electrocatalysts for overall water splitting. Particularly, with the initial Ni:Fe ratio of 7:3, the obtained Ni 0.7 Fe 0.3 PS 3 @MXene nanohybrid reveals low overpotential (282 mV) and Tafel slope (36.5 mV dec −1 ) for oxygen evolution reaction (OER) in 1 m KOH solution. Meanwhile, the Ni 0.9 Fe 0.1 PS 3 @MXene shows low overpotential (196 mV) for the hydrogen evolution reaction (HER) in 1 m KOH solution. When integrated for overall water splitting, the Ni 0.7 Fe 0.3 PS 3 @MXene || Ni 0.9 Fe 0.1 PS 3 @MXene couple shows a low onset potential of 1.42 V and needs only 1.65 V to reach a current density of 10 mA cm −2 , which is better than the all noble metal IrO 2 || Pt/C electrocatalyst (1.71 mV@10 mA cm −2 ). Given the chemical versatility of Ni 1− x Fe x PS 3 and the convenient self‐assemble process, the nanohybrids demonstrated in this work are promising for energy conversion applications.