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Single‐atom catalysts (SACs) have received widespread interest for their high atomic efficiency, enriched active sites, excellent catalytic performance, and low cost. However, the agglomeration of single metal atoms and the use of inactive additives for affixing powdery SACs on planar electrodes may reduce the density of active sites, diminish the charge transport to active sites, and thus suppress their performance. Herein, a series of metal–nitrogen–carbon single‐atom aerogels (M‐SAAs, M: Cu, Ni, Au, Ru) are synthesized via a universal strategy, in which the merits of metal organic frameworks and carbon aerogels are perfectly combined to prevent the agglomeration of single metal atoms and overcome the problem of poor electrical conductivity. The as‐prepared M‐SAAs can be directly employed as self‐supporting electrodes for the electrochemical dechlorination of 1,2‐dichloroethane, and outstanding activity and stability are observed. Significantly, the Cu‐SAA with abundant Cu−N4 sites shows an extraordinarily high ethylene production rate of 446 µmol h−1, with a selectivity of 99% and Faradaic efficiency of 64%. Moreover, theoretical calculations are performed to demonstrate the selectivity and activity of different metal active sites. This study provides a new strategy to exploit highly effective SACs and offers an intensive insight into the mechanism of electrochemical dechlorination reactions. [ABSTRACT FROM AUTHOR]

Carbon aerogels are a fascinating three‐dimensional (3D) monolithic porous material with remarkable physicochemical properties, including low density, large surface area, abundant pore structure, high electrical conductivity, chemical stability, environmental compatibility, adjustable surface chemistry, as well as controllable structural features. These properties endow carbon aerogels with excellent adsorption and catalytic performance. Therefore, they are widely applied in environmental chemistry for removing pollutants like oils, toxic organic solvents, dyes, heavy metal ions in aquatic environments, and volatile organic compounds (VOCs), carbon oxides (CO2, CO), nitrogen oxide (NOx), and hydrogen sulfide (H2S) in the atmosphere. In this paper, the preparation processes of carbon aerogels are fully reviewed, and their applications for environmental clean‐up based on adsorption and catalytic action are thoroughly addressed. In each section, the most recent representative studies will be highlighted. Finally, the challenges, outlooks, and prospects in this emerging and promising research field will be briefly discussed. [ABSTRACT FROM AUTHOR]