Ir-RuO<sub><i>x</i></sub> Nanoparticles on WO<sub>3</sub> Ultrafine Nanowires As Catalysts for the Oxygen Evolution Reaction in Acidic Media
Xinyi Li, Zihan Gu, Junfang Cheng, Guozhu Zhang, Fenghua Zheng, Jiawei Huang, Jingxiang Xu, Guanghua Wei, Junliang Zhang
Abstract
Iridium- and ruthenium-based materials show high activity for oxygen evolution reaction (OER) in acidic media while Ru-based catalysts exhibit low stability, but Ir-based materials are limited by their high cost and low reserves. The rational design of the OER electrocatalysts to balance activity, stability, and cost is facing a challenge. Herein, we report a strategy to synthesize Ir-RuO x @WO 3 catalyst using a low-temperature wet reflux method to deposit Ir-RuO x nanoparticles on ultrafine WO 3 nanowires. Due to the metal–metal support interaction (MMSI) between Ir-RuO x and WO 3, the abundant hydroxyl groups on the surface, and the protection of active sites by the mild catalyst synthesis method, Ir-RuO x @WO 3 demonstrates the OER activity with a low overpotential of 148 mV at 10 mA/cm 2 while the total precious metal usage is only 7.673 wt % (2.990 wt % Ir and 4.647 wt % Ru). Besides, with Ru activating the valence state of Ir to improve the activity and Ir stabilizing the Ru site to improve the stability, Ir-RuO x @WO 3 achieved relative activity-stability balance as there was no noticeable degradation when operating at 10 mA/cm 2 for 12 h. This study presents design concepts of acidic OER catalysts to balance activity, stability, and cost, promoting the widespread use of PEMWE technology in industrial settings.