Self-Powered Water Splitting of Ni₃FeN@Fe₂₄N₁₀ Bifunctional Catalyst Improved Catalytic Activity and Durability by Forming Fe₂₄N₁₀ on Catalyst Surface via the Kirkendall Effect

Highly efficient water splitting electrocatalyst for producing hydrogen as a renewable energy source offers potential to achieve net-zero. However, it has significant challenges in using transition metal electrocatalysts as alternatives to noble metals due to their low efficiency and durability, furthermore, the reliance on electricity generation for electrocatalysts from fossil fuels leads to unavoidable carbon emissions. Here, a highly efficient self-powered water splitting system integrated is designed with triboelectric nanogenerator (TENG) and Ni₃FeN@Fe₂₄N₁₀ catalyst with improved catalytic activity and durability. First, the durability of the Ni₃FeN catalyst is improved by forming N, P carbon shell using melamine, polyetherimide, and phytic acid. The catalyst activity is improved by generating Fe₂₄N₁₀ in the carbon shell through the Kirkendall effect. The synthesized Ni₃FeN@Fe₂₄N₁₀ catalyst exhibited excellent bifunctional catalytic activity (η_OER = 261.8 mV and η_HER = 151.8 mV) and remarkable stability (91.7% in OER and 90.5% in HER) in 1 m KOH. Furthermore, to achieve ecofriendly electricity generation, a rotation-mode TENG that sustainably generate high-performance is realized using butylated melamine formaldehyde. As a result, H₂ is successfully generated using the integrated system composed of the designed TENG and catalyst. The finding provides a promising approach for energy generation to achieve net-zero.