Table 3.

A summary of the major characterizations techniques for proving the existence of single‐atom identity

Techniques	Advantages	Disadvantages
AC‐STEM	Straightforward	Statistically limited, only providing 2D instead of 3D projection information
XAF	Providing information of the whole sample, electronic state, and coordination environment	Average information, not conclusive for every atomic center
CO‐DRIFT	Site‐specific, information on electronic state	Charge‐dependent, SAC, and small NP might not be easily differentiated, not applicable for metals with bad adsorption for CO and dark‐colored supports
STM	Straightforward	Statistically limited, not applicable for samples with poor conductivity
Titration	General approach, providing information of exposed metal atoms	Indirect and inconclusive