One-dimensional iridium-based nanowires for efficient water electrooxidation and beyond

Abstract

The sluggish reaction kinetics of oxygen evolution reaction (OER) has largely lowered the efficiency of electrochemical water splitting. Ir represents one of the state-of-the-art electrocatalysts for promoting OER especially in acidic electrolytes. However, it remains a formidable challenge to synthesize high-quality one-dimensional (1D) Ir-based nanostructures for improved electrocatalytic performance. Herein, a template-assisted synthesis method is reported wherein 1D porous Ir-Te nanowires (Ir-Te NWs) are synthesized with Te NWs serving as the template. The Ir-Te NWs exhibit highly enhanced OER performance compared to commercial IrO₂ and Ir/C. In detail, the overpotentials to reach 10 mA·cm⁻² are 248 and 284 mV in 1 M KOH and 0.5 M H₂SO₄, respectively, much lower than those of commercial catalysts. The Ir-Te NWs also show smaller Tafel slopes than commercial IrO₂ and Ir/C, signifying faster reaction kinetics. Besides, much more durable OER activity can be maintained for Ir-Te NWs with negligible decay during 25 and 20 h stability tests in 1 M KOH and 0.5 M H₂SO₄, respectively. Further analysis indicates that the significantly improved OER performance of Ir-Te NWs could be ascribed to the larger electrochemical surface area and smaller electrical resistance. More significantly, the templated synthesis of Ir-Te NWs can be facilely extended to the fabrication of other metal-Te NWs including Ru-Te, Rh-Te and Pt-Te NWs. The design and synthesis of 1D metal-based NWs in this work provide important inspiration for the synthesis of diversified 1D metallic nanostructures with distinctly enhanced catalytic performance and beyond.