Strong Electronic Coupling between Ultrafine Iridium–Ruthenium Nanoclusters and Conductive, Acid-Stable Tellurium Nanoparticle Support for Efficient and Durable Oxygen Evolution in Acidic and Neutral Media
Junyuan Xu, Zan Lian, Bin Wei, Yue Li, Олександр Бондарчук, Nan Zhang, Zhipeng Yu, Ana Araújo, Isilda Amorim, Zhongchang Wang, Bo Li, Lifeng Liu
Abstract
Proton exchange membrane water electrolysis (PEM-WE) has emerged as a promising technology for hydrogen production and shows substantial advantages over conventional alkaline water electrolysis. To enable efficient PEM-WE in acidic media, iridium (Ir)- or ruthenium (Ru)-based catalysts are indispensable to drive the thermodynamically and kinetically demanding oxygen evolution reaction (OER). However, developing Ir/Ru catalysts with high efficiency and long-term durability still remains a formidable challenge. Herein, we report one-pot hydrothermal synthesis of ultrafine IrRu intermetallic nanoclusters loaded on conductive, acid-stable, amorphous tellurium nanoparticle support (IrRu@Te). Benefiting from the large exposed electrocatalytically active surface of ultrafine IrRu clusters and the strong electronic coupling between IrRu and Te support, the as-obtained IrRu@Te catalysts show good catalytic performance for the OER in strong acidic electrolyte (i.e., 0.5 M H2SO4), requiring overpotentials of only 220 and 303 mV to deliver 10 and 100 mA cm–2 and able to sustain continuous OER electrolysis up to 20 h at 10 mA cm–2 with minimal degradation. Moreover, IrRu@Te exhibits high specific activity, illustrating intrinsically better performance compared with that of unsupported IrRu and other commercial Ir- and Ru-based catalysts. It also demonstrates unprecedentedly high mass activity of 590 A gIrRu–1 at an overpotential of 270 mV, outperforming most Ir- and Ru-based OER catalysts reported in the literature. Furthermore, IrRu@Te catalysts reveal good OER performance in neutral electrolyte as well, holding great potential to be used for PEM-WE in environmentally friendly conditions. Density functional theory (DFT) calculations based on oxidized IrRu confirm that the catalyst/support coupling results in a lower energy barrier for the oxygen–oxygen bonding formation, offering a rational explanation to the experimentally observed OER performance.