Intercalating Bulk Gold Crystal Into Ordered Single Atoms

Gold single atoms (GSAs) have attracted considerable attentions due to their potential in electrocatalytic and photocatalytic reactions. However, achieving high gold density in conventional wet-solution or mechanical approaches remains currently challenging, apart from uncontrolled spatial on-support distributions, undesired bi-products and wastes. Here we show that single gold atoms can be synthesized and patterned via a top-down intercalation method, in which the topmost layer of gold (100) crystal evolves into isolated single atoms (conversion rate up to 25%) chiseled by a phosphorus monolayer. Scanning tunneling microscopy, X-ray photoemission spectroscopy, and density functional theory calculations reveal that GSAs assemble into well-ordered (2 × 2) arrays without thermodynamic tendency for coalescence and weakly couple with the underlying non-planar phosphorus layer toward efficient hydrogen evolution reaction and oxygen evolution reaction catalysis. The on-surface formation of GSAs can be readily tailored by varying the post-annealing temperature and durations. This protocol is defect-free, solvent-free, eco-friendly, scalable, and could regenerate a batch-to-batch of fresh GSAs arrays via a simple sputtering and intercalation process in case of catalyst deactivation. This work opens a green and sustainable way for the facile preparation of high-density GSAs for efficient on-surface electro-/photo-catalytic applications.