The electrochemical nitrogen reduction reaction (NRR) is a very efficient method for sustainable NH3 production, but it requires effective catalysts to expedite the NRR kinetics and inhibit the concomitant hydrogen evolution reaction (HER). Two-dimensional (2D)/2D interface engineering is an effective method to design powerful catalysts due to intimate face-to-face contact of two 2D materials that facilitates the strong interfacial electronic interactions. Herein, we explored a 2D/2D MoS2/C3N4 heterostructure as an active and stable NRR catalyst. MoS2/C3N4 exhibited a conspicuously improved NRR performance with an NH3 yield of 18.5 μg h–1 mg–1 and a high Faradaic efficiency (FE) of 17.8% at −0.3 V, far better than those of the individual MoS2 or C3N4 component. Density functional theory calculations revealed that the interfacial charge transport from C3N4 to MoS2 could enhance the NRR activity of MoS2/C3N4 by promoting the stabilization of the key intermediate *N2H on Mo edge sites of MoS2 and concurrently decreasing the reaction energy barrier. Meanwhile, MoS2/C3N4 rendered a more favorable *H adsorption free energy on S edge sites than on Mo edge sites of MoS2, thereby protecting the NRR-active Mo edge sites from the competing HER and leading to a high FE.

Electrocatalytic N2 reduction reaction (NRR) provides an effective and renewable approach for artificial NH3 production, but still remains a grand challenge because of the low NH3 yield and Faradaic efficiency (FE). Herein, we reported that the SnO2 quantum dots (QDs) supported on reduced graphene oxide (RGO) could efficiently and stably catalyze NRR at ambient conditions. The NRR performance of resulting SnO2/RGO was studied by both experimental techniques and density functional theory calculations. It was found that the ultrasmall SnO2 QDs (2 nm) grown on RGO could provide abundant sites for efficient N2 adsorption. Significantly, the strongly electronically coupled SnO2 QDs and RGO brought about the enhanced conductivity and the decreased work function, which led to a considerably lowered energy barrier of *N2 → *N2H that was the rate-determining step of the NRR process. Meanwhile, the SnO2/RGO exhibited inferior hydrogen evolution reaction activity. As a result, the SnO2/RGO delivered a high NH3 yield of 25.6 μg h–1 mg–1 (5.1 μg cm–2h–1) and an FE of 7.1% in 0.1 M Na2SO4 at −0.5 V (vs RHE), together with the outstanding selectivity and stability, endowing it as a promising electrocatalyst for N2 fixation.

Density functional theory calculations revealed that CoO possessed poor HER activity but favorable NRR activity. CoO quantum dots (2–5 nm) supported on graphene exhibited a high NH3 yield of 21.5 μg h−1 mg−1 and a faradaic efficiency of 8.3% at −0.6 V vs. RHE under ambient conditions, superior to most of the reported NRR catalysts.

Graphene nanoplatelets (GNPs) exhibit ultra‐high strength and elastic modulus. Therefore, they are potential ideal reinforcements in metal–matrix composites (MMCs). In this work, we report the use of GNPs to strengthen the bulk Cu‐matrix composites. GNP reinforced Cu‐matrix (GNP/Cu) composites were prepared by a combination of the ball milling and hot‐pressing processing, and their mechanical properties were investigated. Microstructure studies indicated that the GNPs with 0–8 vol.% contents were well dispersed in the Cu matrix by ball milling. Compared to unreinforced Cu, the GNP/Cu composites showed a remarkable increase in yield strength and Young's modulus up to 114 and 37% at 8 vol.% GNP content, respectively. The extraordinary reinforcement is attributed to the homogeneous dispersion of GNPs and grain refinement. However, the mechanical improvement of GNP/Cu composites was still below the theoretical value. The possible reasons for this deviation were discussed and the methods for further mechanical improvement of GNP/Cu composites were proposed.

Current artificial NH3 synthesis relies heavily on the Haber–Bosch process that involves enormous energy consumption and huge CO2 emission. The electrochemical N2 reduction reaction (NRR) offers an eco-friendly and sustainable alternative but demands cost-effective and efficient NRR electrocatalysts. Herein, NiO nanodots (∼2 nm) supported on graphene (NiO/G) were developed as a high-performance NRR electrocatalyst at ambient conditions. Electrochemical tests indicated that the NiO/G exhibited a high NH3 yield (18.6 μg h–1 mg–1) and Faradaic efficiency (7.8%) at −0.7 V vs reversible hydrogen electrode, outperforming the most reported NRR electrocatalysts. Experimental and density functional theory (DFT) results revealed that NiO was the dominating active center, and nanodot structure enabled the NiO to expose more active sites. DFT results further demonstrated that the distal associative route was the preferable NRR pathway with *N2 → *NNH being the rate-determining step.

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Electrochemical reduction of nitrate to ammonia (NO 3 RR) holds a great promise for attaining both NH 3 electrosynthesis and wastewater purification. Herein, single-atom Bi alloyed Pd metallene (Bi 1 Pd) is reported as a highly effective NO 3 RR catalyst, showing a near 100% NH 3 -Faradaic efficiency with the corresponding NH 3 yield of 33.8 mg h −1 cm −2 at −0.6 V versus RHE, surpassing those of almost all ever reported NO 3 RR catalysts. In-depth theoretical and operando spectroscopic investigations unveil that single-atom Bi electronically couples with its neighboring Pd atoms to synergistically activate NO 3 − and destabilize *NO on Bi 1 Pd, leading to the reduced energy barrier of the potential-determining step (*NO→*NOH) and enhanced protonation energetics of NO 3 − -to-NH 3 pathway.