Engineering 2D nickel boride/borate amorphous/amorphous heterostructures for electrocatalytic water splitting and magnetism

Abstract

The rational engineering of 2D amorphous/amorphous heterostructures is considered a promising route to finely tune the intrinsic properties of 2D nanomaterials. Herein, we demonstrate a simple strategy to engineer 2D nickel boride/borate amorphous/amorphous heterostructures using a simple one-pot chemical reduction method, and provide a detailed insight into their electrocatalytic and magnetic performance. All heterostructures exhibited the same morphology with an amorphous phase. Their nickel content was finely tuned by adjusting the concentration of sodium borohydride during synthesis. It was demonstrated that the heterostructures with the highest nickel content exhibited the highest values of measured current (12.8 nA) and lowest values of measured resistance (396 MΩ). The same heterostructure demonstrated better magnetic performance when compared to the other two heterostructures. In contrast, HER electrocatalytic activity was the highest for the heterostructure that exhibited the highest surface area (86.7 m² g⁻¹), with an overpotential value of 0.87 V vs. RHE at −10 mA cm⁻², revealing a direct correlation with the physical dimensions of the heterostructure. This work opens up new directions in the rational engineering of 2D metal boride/borate amorphous/amorphous heterostructures, with optimal intrinsic properties for energy applications. The heterostructures can be easily upscaled to an industrial scale due to their production simplicity.