Phosphatizing Engineering of Perovskite Oxide Nanofibers for Hydrogen Evolution Reaction to Achieve Extraordinary Electrocatalytic Performance

Abstract Perovskite oxides with tailored elements and structures endow promising electrocatalytic properties for hydrogen evolution reaction (HER) due to considerable activity and satisfactory long‐term operating stability. However, the synthesis of 1D perovskite nanostructures with anion dopants remains a challenge, as well as insights into the performance origin from experimental and theoretical views. Herein, combined with electrospinning and phosphatizing strategies, P‐doped Pr_0.5La_0.5BaCo₂O_5+δ perovskite nanofibers (P‐PLBC‐F) are reported for highly active HER catalysts. The P‐PLBC‐F catalyst outperforms the classic perovskites and can be comparable to the commercial Pt/C (wt_Pt = 20%) benchmark, exhibiting a Tafel slope of −32.9 mV dec⁻¹ and overpotential of −307 mV at 500 mA cm⁻² _disk in alkaline media. The highly catalytic activity benefits from the desired 1D nanostructure, steered electronic structures (charge transfer energy Δ_Co‐P = 0.79 eV) and Gibbs free energy for the H^* desorption (1.02 eV) induced by the P³⁻ doping, as supported by density functional theory calculations. The findings described here unveil the phosphatizing mechanism of the perovskites for catalyzing the hydrogen production, and broaden horizons in terms of rational designs of novel perovskite‐based catalysts for sustainable energy.