Self-driven dual hydrogen production system based on a bifunctional single-atomic Rh catalyst

Abstract

Electrocatalytic hydrogen evolution is an efficient and economical technology to address environmental contamination and energy crises, but the development of such a high-efficiency and energy-saving sustainable hydrogen production system remains a great challenge. Here, we present a novel strategy to design a self-driven dual hydrogen production system for efficient hydrogen production based on highly-dispersed single Rh atoms supported on an oxygen-functionalized Ti₃C₂O_x MXene (Rh-SA/Ti₃C₂O_x) catalyst. The bifunctional Rh-SA/Ti₃C₂O_x catalyst exhibits remarkable catalytic activities towards both the pH-universal hydrogen evolution reaction (HER) and hydrazine oxidation reaction (HzOR). Using Rh-SA/Ti₃C₂O_x as the electrode in the self-driven dual hydrogen production system by combining a Zn–H₂ battery and overall hydrazine splitting units, an ultra-high H₂ generation rate of 45.77 mmol h⁻¹ can be achieved. Density functional theory calculations indicate that the atomically dispersed single Rh atoms not only make the free energy of adsorbed H (ΔG_*H) more thermoneutral for the HER but also largely decrease the free-energy barrier of the dehydrogenation of adsorbed NHNH₂ for the HzOR.