Abstract:Through a coordination-driven self-assembly strategy of ultrathin tannic acid (TA) layer and Ru ions, the electronic structure (Ni(OH)2-TA-Ru) rich in 2 nm Ru nanoparticles on the surface of nickel hydroxide was optimized. Electrochemical evaluations, structural characterizations, and density functional theory (DFT) calculations were utilized to assess the hydrogen evolution reaction (HER) activity, long-term operation stability, and electronic structure characteristics of Ru active sites. It is found that Ni(OH)2-TA-Ru only requires 53 and 70 mV overpotentials at 100 mA/cm2 in 1 M KOH and alkaline seawater (1 M KOH + seawater), respectively, which are 51.7% and 36.2% lower than that of Pt/C/NF (109.7 mV). Chronopotentiometric tests are stable for 100 h and 72 h, respectively. The TA ultrathin layer modified Ni (OH)2 support induces the formation of electron-deficient Ru species, downshifting the Ru d-band center by 0.35 eV. This electronic restructuring weakens Ru-H bond strength, accelerates the desorption of hydrogen intermediates (H*), and promotes the Heyrovsky rate-determining step and enhancing alkaline HER kinetics.
