Engineering A-site vacancies and Mo substitution in La₂CuO₄ for high-performance bifunctional water-splitting...

Designing electrocatalysts that concurrently offer high activity, long-term durability, and low cost remains a major challenge in sustainable energy conversion technologies. In particular, bifunctional catalysts capable of efficiently catalyzing both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are highly desirable for practical water-splitting systems. Herein, La_1.9Cu_0.9Mo_0.1O_4-δ (d-LCMO-Ar) ("d" refers to deficiency) is synthesized via a citric-acid-assisted method followed by argon annealing, using a Ruddlesden-Popper parent phase as a structural platform to engineer enhanced bifunctional performance. The optimized catalyst achieves current densities of 10 and 100 mA cm^-2 at overpotentials of 258 and 500 mV for the OER and -117 and -323 mV for the HER, respectively, in 1 M KOH. Moreover, d-LCMO-Ar maintains a stable current density of 50 mA cm^-2 over 50 h, demonstrating excellent durability, and exhibits a large electrochemical surface area (183.7 cm²), low Tafel slopes of 67 mV dec^-1 (OER) and 157 mV dec^-1 (HER), as well as high turnover frequencies of 6.51 s^-1 (OER) and 13 s^-1 (HER). Collectively, these attributes highlight d-LCMO-Ar as a promising and cost-effective alternative to noble-metal based catalysts for alkaline water-splitting applications.