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In recent years, there has been a substantial surge in the investigation of transition‐metal dichalcogenides such as MoS₂as a promising electrochemical catalyst. Inspired by denitrification enzymes such as nitrate reductase and nitrite reductase, the electrochemical nitrate reduction catalyzed by MoS₂with varying local atomic structures is reported. It is demonstrated that the hydrothermally synthesized MoS₂containing sulfur vacancies behaves as promising catalysts for electrochemical denitrification. With copper doping at less than 9% atomic ratio, the selectivity of denitrification to dinitrogen in the products can be effectively improved. X‐ray absorption characterizations suggest that two sulfur vacancies are associated with one copper dopant in the MoS₂skeleton. DFT calculation confirms that copper dopants replace three adjacent Mo atoms to form a trigonal defect‐enriched region, introducing an exposed Mo reaction center that coordinates with Cu atom to increase N₂selectivity. Apart from the higher activity and selectivity, the Cu‐doped MoS₂also demonstrates remarkably improved tolerance toward oxygen poisoning at high oxygen concentration. Finally, Cu‐doped MoS₂based catalysts exhibit very low specific energy consumption during the electrochemical denitrification process, paving the way for potential scale‐up operations.

 

Aryl chlorides (ArCl) or aryl fluorides (ArF) were used in polycondensation reactions to form poly(arylene ether sulfone)s (PAES). Interestingly, the kinetics of the ArF reaction fit a third-order rate law, which is attributed to the activation of the carbon–fluorine bond by two potassium cations (at least one bound to phenolate), which form a three-body complex. The ArCl monomer follows a second-order rate law, where a two-body complex forms at the initial state of the aromatic nucleophilic substitution (S N Ar) pathway. These metal cation-activated complexes act as intermediates during the attack by the nucleophile. This finding was reproduced with either the potassium or the sodium counterion (introduced via potassium carbonate or sodium carbonate). Through a combination of experimental analysis of reaction kinetics and computational calculations with density functional theory (DFT) methods, the present work extends the fundamental understanding of polycondensation mechanisms for two aryl halides and highlights the importance of the CX–metal interaction(s) in the S N Ar reaction, which is translational to other ion-activated substitution reactions.