One-Pot Synthesis of Alloy Ir–Cu Microspheres with Excellent Electro-Catalytic Activity Toward Oxygen Evolution Reaction under Acidic Conditions

The development of catalysts with high efficiency and stability in acidic electrolytes for oxygen evolution reaction (OER) is critical to water electrolyzers and renewable energy conversion and has been eagerly explored in the shape-controlled synthesis of noble metals such as Ir and Ru. However, the expensive prices of Ir and Ru severely hamper their wide use in OER. In this work, we show an efficient method for the one-pot synthesis of Ir0.4Cu0.6 microspheres. Electrochemical tests showed that the Ir–Cu microspheres as-synthesized delivered a prominent electrocatalytic activity toward OER in an acidic electrolyte with low overpotential (255 mV at 10 mA cm–2) and a small Tafel slope of 53.3 mV decade–1. They were much better than those of commercial Ir/C (331 mV at 10 mA cm–2 and Tafel slope of 100 mV decade–1). Moreover, the Ir0.4Cu0.6 as-synthesized also exhibited good stability for OER under acidic conditions, that is, after 30,000 s, the change of its potential was quite small in the chronopotentiometry test. The high catalytic performance could originate from the synergistic electronic interaction between iridium and copper atoms, which could modify the d-band center of iridium.