Self-reconstruction in 2D nickel thiophosphate nanosheets to boost oxygen evolution reaction

Abstract Development of robust and non-precious metal electrocatalysts for oxygen evolution reaction is central to sustainable electrochemical energy storage and conversion technologies. Self-reconstruction of electrocatalysts plays an important role during oxidation reactions. Exploring the correlation between the intrinsic electronic structures with the reconstruction in the layered metal thio (seleno) phosphates is highly expected but inadequate. In this paper, we report the uncovering of the surface self-reconstruction behavior of NiPS 3 nanosheets with remarkable electrochemical performance in an oxygen evolution reaction (OER). Our studies reveal that the orbital hybridization between S and P effectively modulates the surface electronic structure of Ni, lowering the Gibbs free energy of OH − adsorption and promoting the Ni 2+ oxidation. As a result, this synergistic effect and the in-situ formed NiPS 3 –NiOOH heterostructure lead to impressive catalytic kinetic with a much small Tafel slope of 51 mV dec −1 and excellent stability in our as-synthesized NiPS 3 nanosheets. Our work provides fundamental understanding of the surface reconstruction of the promising metal thio (seleno) phosphates electrocatalysts toward OER from the view of intrinsic electronic structure.