Cu(OH) ₂ @MoO ₃ Nanorod Heterostructure for Efficient Overall Electrocatalytic Water Splitting in an Alkaline Medium

The rational design of cost-effective electrocatalysts with superior catalytic activity for overall water splitting (OWS) continues to pose a significant challenge. The combination of oxygen vacancies and the adaptable electronic structure in the Cu(OH)₂ heterostructure has made them highly appealing for catalytic applications. Herein, the Cu(OH)₂ and MoO₃ (Cu@MoO₃) nanorod heterostructure was prepared via a simple hydrothermal process. Subsequently, Cu(OH)₂ was anchored into the MoO₃ nanorods using a coprecipitation method. The X-ray photoelectron spectroscopy result confirmed the existence of mixed Mo⁵⁺ and Mo⁶⁺ oxygen states and oxygen vacancies in the Cu@MoO₃ heterostructure. The Cu@MoO₃-3 electrocatalyst exhibited outstanding hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performance, requiring overpotentials of 78 and 308 mV at 10 mA cm⁻² in 1 M KOH, respectively. The constructed electrolyzer exhibits impressive durability, achieving 10 mA cm⁻² at 1.56 V along with a Faradaic efficiency of 86.44% for O₂ production. This study demonstrates the successful synthesis of a catalyst via a hydrothermal process, highlighting its promising potential for future applications.