Encapsulating vanadium nitride nanodots into N,S-codoped graphitized carbon for synergistic electrocatalytic nitrogen reduction and aqueous Zn-N2 battery

Electrochemical nitrogen reduction reaction (ENRR) is a promising strategy for mild electrosynthesis of ammonia but needs highly efficient electrocatalytic centers. Herein, vanadium nitride nanodots embedded in ultrathin N,S-codoped carbon matrix (denoted as VN@NSC) are developed to serve as a promising catalyst for efficient ENRR, showing robust stability, high NH3 yield and pH independence for the electrochemical synthesis of ammonia. Besides, VN@NSC was employed as N-2 cathode for assembled Zn-N-2 aqueous battery, which shows a significant potential for practical applications. Such remarkable activity of VN@NSC is ascribed to structural advantages and synergistic interaction among the components. Specifically, N,S-codoped carbon (NSC), as a stable support with sufficient carbon defects, not only plays vital role in size-limited growth of VN nanoparticles but also acts as a brilliant capturer for adsorption and activation of N 2 molecules. Meanwhile, VN nanodots encapsulated in the NSC capturer function as a highly efficient converter for N-2 to NH3, and this inlaid structure could effectively prevent VN nanodots shedding and deactivation resulted from hydrogen spillover. Furthermore, N-15 isotopic labeling experiments give sufficient evidence for accurate detection of NH3 yields of VN@NSC, and electrochemical-based in situ Fourier transform infrared spectroscopy provides reasonable insight into the underlying ENRR mechanism.

Automated summary

This study developed a promising catalyst VN@NSC with VN nanodots embedded in an ultrathin N,S-codoped carbon matrix for efficient ENRR, demonstrating high activity, stability, pH independence, and high NH3 yield. Additionally, VN@NSC showed significant potential for practical applications in Zn-N-2 aqueous batteries.