Single-Atom Anchored g-C3N4 Monolayer as Efficient Catalysts for Nitrogen Reduction Reaction

Electrochemical N-2 reduction reaction (NRR) is a promising approach for NH3 production under mild conditions. Herein, the catalytic performance of 3d transition metal (TM) atoms anchored on s-triazine-based g-C3N4 (TM@g-C3N4) in NRR is systematically investigated by density functional theory (DFT) calculations. Among these TM@g-C3N4 systems, the V@g-C3N4, Cr@g-C3N4, Mn@g-C3N4, Fe@g-C3N4, and Co@g-C3N4 monolayers have lower Delta G(*NNH) values, especially the V@g-C3N4 monolayer has the lowest limiting potential of -0.60 V and the corresponding limiting-potential steps are *N-2+H++e(-)=*NNH for both alternating and distal mechanisms. For V@g-C3N4, the transferred charge and spin moment contributed by the anchored V atom activate N-2 molecule. The metal conductivity of V@g-C3N4 provides an effective guarantee for charge transfer between adsorbates and V atom during N-2 reduction reaction. After N-2 adsorption, the p-d orbital hybridization of *N-2 and V atoms can provide or receive electrons for the intermediate products, which makes the reduction process follow acceptance-donation mechanism. The results provide an important reference to design high efficiency single atom catalysts (SACs) for N-2 reduction.

Automated summary

This study systematically investigates the catalytic performance of 3d transition metal (TM) atoms anchored on s-triazine-based g-C3N4 (TM@g-C3N4) in electrochemical N-2 reduction reaction (NRR) using density functional theory (DFT) calculations. Among the TM@g-C3N4 systems, V@g-C3N4 shows the lowest limiting potential and ΔG(*NNH) values. The results provide important insights for designing high efficiency single atom catalysts (SACs) for N-2 reduction.