Quantum confined one-dimensional lepidocrocite titanate catalyst for superior electrocatalytic oxygen evolution performance

Intercalated one-dimensional Lepidocrocite (1DL) structures have emerged as promising platforms for diverse applications due to their structural versatility and functional tunability. We recently developed a highly scalable, inexpensive and simple technique to synthesize quantum confined 1DL nanofilaments, NFs. X-ray diffraction, density functional theory and transmission electron microscopy analyses revealed that the building blocks are 1D NFs with cross-sectional dimensions of ≈ 5 × 7 Å. These nanofilaments stack along [020] and grow along the [100] direction. Herein, we demonstrate that the oxygen evolution reaction (OER) performance can be significantly enhanced through the incorporation of cobalt and iron cations via intercalation. One of the resulting compositions, co-doped with Co and Fe in a 70:30 M ratio displayed an ultralow overpotential of 251 mV at a current density of 10 mA cm −2 . Long-term durability tests on this electrode (100 h at 10 mA/cm 2 , and 150 h at 500 mA/cm 2 ) indicated that the electrocatalyst was highly stable, exhibiting minimal degradation. Post-stability analysis reveals that the material remains on the electrode surface with uniform distribution and compositions. This work provides a new avenue for the development of efficient 1DL-based electrocatalysts through transition metal cation intercalation to enhance the OER activity. • New quantum-confined, water-stable 1D inorganic titanates developed. • 5x7Å 2 in cross-section, 1D lepidocrocite titanate with band gap energy of 4 eV. • Kilogram-scale production achieved using only plastic bottles and hot plates. • 1DL-CoFe-70:30 (molar ratio) shows 251 mV overpotential at 10 mA cm −2 . • Stable for 100 h at 10 mA/cm 2 and at 500 mA/cm 2 for 150 h.