Synergistic phosphorized NiFeCo and MXene interaction inspired the formation of high-valence metal sites for efficient oxygen evolution

Exploring low-cost, high-performance, and stable electrocatalysts toward the oxygen evolution reaction (OER) is highly desired but remains challenging. Transition metal hydroxide has been wildly utilized as a promising candidate, but practical implementation is impeded by insufficient catalytic activity, easy agglomeration, and poor conductivity. Here, we report that both phosphorization and combination with MXnene can improve the catalysts' intrinsic activity and conductivity. Besides, MXene also prevents the agglomeration of the nanoparticles, resulting in the enhanced exposure of active sites. Experimental characterizing and density functional theory simulations revealed that P species can attract electrons to promote the formation of high-valence states of adjacent metal atoms, and coupling MXene support can effectively modulate the electronic structure and optimize the d -band center, which boosts the OER performance. Consequently, the optimized NiFeCoP/Mxene catalyst exhibits a low overpotential of 240 mV at a current density of 10 mA cm -2 , a small Tafel slope of 55 mV dec -1 , and superior long-term stability of 40 h in 1 M KOH electrolyte, which is superior to other counterparts. (c) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

In this study, the combination of phosphorization and MXnene was found to improve the activity and conductivity of transition metal hydroxide catalysts for the oxygen evolution reaction (OER). MXene also prevented the agglomeration of nanoparticles, increasing the exposure of active sites. Experimental and simulation results showed that the optimized NiFeCoP/Mxene catalyst exhibited excellent OER performance in potassium hydroxide electrolyte.