Strain Engineering of the NiTe/Ni2P Heterostructure to Boost the Oxygen Evolution Reaction

Discovering highly efficient and stable non-preciousmetal catalystsfor the oxygen evolution reaction (OER) is crucial for energy conversionin water splitting. However, preparing high-performance OER catalystsand elucidating the structural changes in the process are still challenging.Herein, we synthesize the NiTe/Ni2P heterostructure anddemonstrate the strain engineering of NiTe/Ni2P via thelattice incompatibility between the phosphide and the telluride. Thestrain engineering of the NiTe/Ni2P heterostructure notonly significantly boosts the OER activity but also effectively stabilizesthe intrinsic structure of the catalyst after the OER process by usingthe in situ-produced metal salt as a protection layer.After the OER stability test, no oxyhydroxide phase is observed, and in situ Raman spectroscopy reveals that a voltage-dependentphase transition appears during the OER, which is different from mostpreviously reported Ni-based catalysts, for which the generation ofirreversible NiOOH occurs after the OER. Density functional theorycalculations further reveal that the tensile strain of Ni2P will inhibit the presence of irreversible phase transitions ofNi(2)P into NiOOH due to the weak adsorption ability of theoxygen species caused by strain engineering. In short, this work opensa new gate for using strain nanotechnology to design high-performanceOER catalysts.

Automated summary

This study synthesizes the NiTe/Ni2P heterostructure and demonstrates the strain engineering of NiTe/Ni2P through the lattice incompatibility between the phosphide and the telluride. The strain engineering significantly enhances the oxygen evolution reaction (OER) activity and stabilizes the catalyst's intrinsic structure. Notably, a voltage-dependent phase transition appears during the OER, which is different from most previously reported Ni-based catalysts. Density functional theory calculations reveal that the tensile strain of Ni2P inhibits the irreversible phase transitions of Ni(2)P into NiOOH. Overall, this work presents a new approach for designing high-performance OER catalysts using strain nanotechnology.