Fabrication of Flexible Nickel Phosphide ITO‐PET Electrode Using a Screen‐Printing Strategy for Robust Electrochemical Water Electrolysis

The development of cost‐effective, stable, and highly active electrocatalysts is crucial for improving the kinetics of overall water splitting in alkaline media, ultimately reducing hydrogen production costs. In this work, we synthesized nickel phosphide nanostructures (Ni 2 P NSs) and introduced phosphorus vacancies via annealing. To achieve a durable and efficient electrode, the material was coated onto ITO‐PET substrates using a screen‐printing technique. The phosphorus vacancies effectively modulate active sites, enhancing the electrocatalytic performance of Ni 2 P NSs, while the ITO‐PET provides a flexible conductive platform that enables stable catalyst immobilization through the screen‐printing method. Unlike previously reported Ni 2 P‐based catalysts that primarily focus on powder systems or rigid substrates, this work integrates vacancy engineering with a scalable screen‐printing strategy on a flexible, conductive platform, thereby enabling enhanced catalytic activity and mechanical robustness. The vacancy‐rich Ni 2 P NSs (Ni 2 P‐400) coated on ITO‐PET demonstrated remarkable electrocatalytic activity, achieving low overpotentials of 318 mV for HER and 316 mV for OER at 100 mA cm −2 . The prepared electrode materials also showed excellent performance towards overall water electrolysis in a two‐electrode setup, requiring only 1.87 V to reach 100 mA cm −2 , and maintained stability for 90 h under alkaline conditions.