Synergistic Catalysis of Single-Atom Alloys and Ordered Indium Clusters in Aluminum Sheet for Enhanced Hydrogen Production.

Abstract

The hydrolysis of aluminum (Al) in pure water is regarded as a greatly promising strategy for on-demand hydrogen supply due to the high energy density of Al and the operational simplicity of the process. However, its precise reaction mechanism remains poorly understood. Here, we report an efficient smelting method to fabricate AlGaIn alloy sheet and elucidate the atomic-scale reaction pathways of the hydrolysis process. Spherical aberration correction electron microscopy, X-ray absorption fine structure, and in situ scanning electron microscopy reveal that AlGaIn alloy sheet shows a typical layered structure with rich grain boundaries and is composed of a uniform reactive surface AlGa film, AlGa₁ single-atom alloys, and highly ordered In atom clusters. An optimized AlGaIn alloy sheet demonstrates excellent hydrolysis performance at room temperature when directly immersed in pure water without prior pulverization. Ambient-pressure x-ray photoelectron spectroscopy and density functional theory (DFT) calculations confirm that the hydrolysis reaction is initiated at the active sites on the reactive AlGa film and is further accelerated by a cooperative catalytic effect of AlGa₁ single-atom alloys and highly ordered In atom clusters. In particular, In clusters mainly facilitate water dissociation, while AlGa₁ single-atom alloys are responsible for enhancing *H combination and Al spillover.