Strain Engineering of the NiTe/NiP Heterostructure to Boost the Oxygen Evolution Reaction.

Discovering highly efficient and stable non-precious metal catalysts for the oxygen evolution reaction (OER) is crucial for energy conversion in water splitting. However, preparing high-performance OER catalysts and elucidating the structural changes in the process are still challenging. Herein, we synthesize the NiTe/NiP heterostructure and demonstrate the strain engineering of NiTe/NiP via the lattice incompatibility between the phosphide and the telluride. The strain engineering of the NiTe/NiP heterostructure not only significantly boosts the OER activity but also effectively stabilizes the intrinsic structure of the catalyst after the OER process by using the -produced metal salt as a protection layer. After the OER stability test, no oxyhydroxide phase is observed, and Raman spectroscopy reveals that a voltage-dependent phase transition appears during the OER, which is different from most previously reported Ni-based catalysts, for which the generation of irreversible NiOOH occurs after the OER. Density functional theory calculations further reveal that the tensile strain of NiP will inhibit the presence of irreversible phase transitions of NiP into NiOOH due to the weak adsorption ability of the oxygen species caused by strain engineering. In short, this work opens a new gate for using strain nanotechnology to design high-performance OER catalysts.