In this work, a few-layered MoSe 2 on Ti 3 C 2 T x MXene (MoSe 2 /Ti 3 C 2 T x ), obtained via a simple one-step hydrothermal synthesis and thermal annealing, is investigated for its potential application as an active electrochemical nitrogen reduction reaction (eNRR) catalyst. The MoSe 2 /Ti 3 C 2 T x catalyst achieved an NH 3 yield rate of 56.96 μg h −1 mg cat −1 at −0.50 V vs RHE and a Faradic efficiency (FE) of 14.08% at −0.35 V vs RHE with remarkable electrochemical stability. Meanwhile, the density functional theory (DFT) calculations suggest that Mo atoms are active sites for eNRR, and the distal pathway is the preferred route for NH 3 formation on MoSe 2 /Ti 3 C 2 T x . KEYWORDS: electrocatalysts, N 2 reduction reaction, Ti 3 C 2 T x MXene, few-layer MoSe 2 , density functional theory

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Under the dual pressure of energy crisis and environmental pollution, ammonia (NH3) is an indispensable chemical product in the global economy. The electrocatalytic synthesis of NH3 directly from nitrogen and water using renewable electricity has become one of the most attractive and important topics. Basal plane‐activated boron‐doped MoS2 nanosheets (B−MoS2) as a non‐noble metal catalyst with excellent performance for N2 electroreduction are synthesized by a facile one‐step hydrothermal method. In 0.1 m Na2SO4 solution, MoS2 nanosheets doped with 300 mg boric acid (B−MoS2‐300) give rise to a good ammonia yield rate of 75.77 μg h−1 mg−1cat. at −0.75 V vs. RHE, and an excellent Faradaic efficiency of 40.11 % at −0.60 V vs. RHE. In addition, the B−MoS2‐300 nanosheets show good selectivity and chemical stability, and no hydrazine (N2H4) by‐product is generated during the reaction. 15N isotopic labeling confirms that nitrogen in produced ammonia originates from N2 in the electrolyte. On the one hand, the high conductivity of MoS2 guarantees guarantees a high electron transfer rate from nitrogen to ammonia; on the other hand, the successful incorporation of heteroatom B enlarges the interlayer spacing of MoS2, and the B atom can act as an active site for basal plane activation, providing more active sites for the nitrogen reduction reaction (NRR). Density functional theory calculations show that the doping of B activates the base plane of 1T‐MoS2, which makes the adsorption of N2 on the base plane easier and promotes the NRR.

At present, the research on highly active and stable nitrogen reduction reaction catalysts is still challenging work for the electrosynthesis of ammonia (NH3). Herein, we synthesized atomically dispersed zinc active sites supported on N‐doped carbon nanosheets (Zn/NC NSs) as an efficient nitrogen reduction reaction catalyst, which achieves a high ammonia yield of 46.62 μg h−1 mg−1cat. at −0.85 V (vs RHE) and Faradaic efficiency of 95.8% at −0.70 V (vs RHE). In addition, Zn/NC NSs present great stability and selectivity, and there is no significant change in NH3 rate and Faradaic efficiencies after multiple cycles. The structural characterization shows that the active center in the nitrogen reduction reaction process is the Zn–N4 sites in the catalyst. DFT calculation confirms that Zn/NC with Zn–N4 configuration has a lower energy barrier for the formation of *NNH intermediate compared with pure N‐doped carbon nanosheets (N‐C NSs), thus promoting the hydrogenation kinetics in the whole nitrogen reduction reaction process.