Hollow Bi₂Te₃ nanowire supported Ir for highly active and durable oxygen evolution reaction in proton exchange membrane water electrolysis

The imperative demand for energy paradigm shift toward renewable and sustainable energy sources has intensified interest in proton exchange membrane water electrolysis (PEMWE) as a clean and efficient hydrogen production technology. However, the practical application of PEMWE is hindered by the scarcity and high cost of iridium (Ir), the state-of-the-art electrocatalyst for the oxygen evolution reaction (OER). To reduce Ir loading without compromising performance, we report a novel hollow Bi₂Te₃ (h-Bi₂Te₃) nanowire as a conductive and acid-tolerant support for Ir-based OER electrocatalysts. The h-Bi₂Te₃ nanowires were synthesized via a two-step wet chemical synthesis involving Te nanowire growth and subsequent Bi incorporation, with controlled hollowness induced by modulating the reducing agent concentration. Ir nanoparticles were uniformly deposited onto h-Bi₂Te₃ via polyol method, forming amorphous and well-dispersed Ir catalytic layers. Ir/h-Bi₂Te₃ catalyst achieved an outstanding OER overpotential of 268 mV at 10 mA/cm², a mass activity of 460 mA/mg_Ir at 1.55 V (vs. reversible hydrogen electrode (RHE)), and superior stability over 5 h, surpassing commercial IrO_x/TiO₂, commercial Ir black, and Ir/Te benchmarks. The enhanced performance was attributed to the strong metal–support interaction, improved charge transfer, and enlarged electrochemically active surface area. Moreover, Ir/h-Bi₂Te₃ catalyst demonstrated outstanding single-cell performance of 1.811 V at 2.0 A/cm² with extremely low Ir loading (0.1 mg_Ir/cm²) and long-term durability (a cell voltage increase of 36.6 mV during 100 h at 1.0 A/cm²), confirming its strong potential as a practical anode electrocatalyst for PEMWE. This study highlights the promise of morphology-engineered h-Bi₂Te₃ supports for advancing cost-effective and durable PEMWE systems.