The depletion of energy and increasing environmental pressure have become one of the main challenges in the world today.
Synthetic high-efficiency catalysts bring hope for efficient conversion of energy and effective treatment of pollutants, especially,
single-atom catalysts (SACs) are promising candidates. Herein, we comprehensively summarizes the atomic diffusion strategy, which
is considered as an effective method to prepare a series of SACs. According to the different diffusion forms of the precursors, we
review the synthesis pathways of SACs from three aspects: gas diffusion, solid diffusion and liquid diffusion. The gaseous diffusion
method mainly discusses atomic layer deposition (ALD) and chemical vapor deposition (CVD), both of which carry out gas phase
mass transfer at high temperatures. The solid-state diffusion method can be divided into nanoparticle transformation into single atoms
and solid atom migration. Liquid diffusion mainly describes the electrochemical method and the molten salt method. We hope this
review can trigger the rational design of SACs.