Highly Active and\nRobust Electrocatalyst Based on\nNickel Phosphide Supported by Borophene for Oxygen Evolution Reaction

In recent years, transition-metal phosphides (TMPs) have\nbeen widely\nreported as a new candidate as electrocatalysts for electrochemical\nwater splitting. However, the agglomeration of metal phosphide nanoparticles\nhinders the overall kinetics and stability of such materials. On the\nother hand, it has already recently been revealed that 2D borophene\nnanosheets can act as chemical stabilizers for anchoring nanoparticles\non their surface, boosting charge transfer during oxygen evolution\nreaction (OER). Therefore, here, borophene nanosheets are proposed\nto act as a host of Ni<sub>2</sub>P nanoparticles. The chemical composition\nof the prepared material has been investigated, and the influence\nof the borophene-to-nickel phosphide ratio on the electrochemical\nproperties was tested (B:Ni<sub>2</sub>P = 1:1, 100:1, 10:1, 1:100,\nrespectively). Interestingly, in the composite of borophene_Ni<sub>2</sub>P_1:1, the superior electrocatalytic response was observed,\nwith an overpotential equal to 299 mV, a Tafel slope of 53.6 mV/dec,\nand high durability indicating its promising practical applications\nas an effective replacement for a commercially used electrocatalyst.\nWhat is more, a detailed ex situ study allowed us to demonstrate the\nmechanism of the boosted OER in the presence of borophene_Ni<sub>2</sub>P_1:1, indicating the reaction active species and its intermediates.\nConsequently, the strategy involving the deposition of Ni<sub>2</sub>P nanoparticles on various 2D materials such as graphene and MoS<sub>2</sub> has been employed to demonstrate the viability of this strategy\nas a universal approach for enhancing electrocatalytic activity. Nonetheless,\nthe findings prove that borophene exhibits superior performance in\npromoting the electroactivity of guest nanoparticles.