This study investigates the stability of nonmetal dopants in heterogeneous nano-electrocatalysts under working conditions, revealing that the active sites based on these dopants can collapse when the redox working potential is too low or too high. This phenomenon explains the observed "remarkable catalytic performance" in some cases, which actually originates from in situ formed active sites. The research focuses on several heteroatom-doped nanocatalysts (Bi-F, C-F, and C-N) for CO2RR, HER, ORR, and OER. For example, in CO2RR, the observed high activity and stability of Bi-F are attributed to defective Bi sites formed in situ after the leaching of F, rather than F-based active sites. Similar findings are observed for F- and N-doped carbon catalysts in CO2RR and HER, respectively. However, during ORR, the dopants remain stable, while at more positive potentials for OER, the dopants leach rapidly again. The study provides insights into the real role of heteroatoms in electrocatalysis and offers a protocol for engineering highly efficient active sites through dopant leaching.This study investigates the stability of nonmetal dopants in heterogeneous nano-electrocatalysts under working conditions, revealing that the active sites based on these dopants can collapse when the redox working potential is too low or too high. This phenomenon explains the observed "remarkable catalytic performance" in some cases, which actually originates from in situ formed active sites. The research focuses on several heteroatom-doped nanocatalysts (Bi-F, C-F, and C-N) for CO2RR, HER, ORR, and OER. For example, in CO2RR, the observed high activity and stability of Bi-F are attributed to defective Bi sites formed in situ after the leaching of F, rather than F-based active sites. Similar findings are observed for F- and N-doped carbon catalysts in CO2RR and HER, respectively. However, during ORR, the dopants remain stable, while at more positive potentials for OER, the dopants leach rapidly again. The study provides insights into the real role of heteroatoms in electrocatalysis and offers a protocol for engineering highly efficient active sites through dopant leaching.