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

Abstract

Abstract 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 N2 cathode for assembled Zn-N2 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 N2 molecules. Meanwhile, VN nanodots encapsulated in the NSC “capturer” function as a highly efficient “converter” for N2 to NH3, and this inlaid structure could effectively prevent VN nanodots shedding and deactivation resulted from hydrogen spillover. Furthermore, 15N 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.