Nitrogen (N₂) fixation at ambient condition by electrochemical N₂ reduction reaction (NRR) is energy‐efficient and eco‐friendly as compared to the traditional Harber–Bosch process, but it is extremely challenging. Development and design of high‐performance NRR electrocatalysts are indispensable to achieve the goal. In this work, a strongly coupled hybrid of nano‐Fe₃O₄ with reduced graphene oxide (rGO) is synthesized via an in situ redox hydrothermal approach, and the synthesized Fe₃O₄@rGO hybrid has excellent activity, selectivity, and stability as an NRR catalyst. The NH₃ yield rate of 28.01 μg h^‐1 mg^‐1 at −0.3 V and the Faradaic efficiency (FE) of 19.12% at −0.1 V are obtained in 0.1 M Na₂SO₄ solutions at ambient conditions. The superior NRR performance is attributed to the chemical coupling effect between rGO and nano‐Fe₃O₄ particles, which leads to the enhancement of the binding affinity to N₂ molecules, improvement of the conductivity, and lowering the free energy of reaction for the limiting reaction step. This work provides a facile route in fabricating hybrid NRR catalysts with superior performance and shed lights on the reaction mechanism with theoretical mechanistic calculations.

Lithium-sulfur (Li-S) batteries exhibit the high specific capacity and energy density, but prevented by the low coulombic efficiency and weak cycle life. Herein, we fabricate reduced graphene oxide (r-GO) three-dimensional (3D) foams encapsulating polar mesoporous zinc sulfide (ZnS) nanosheets and subsequently utilize the ZnS/r-GO foams to load sulfur (ZnS/r-GO/S) as cathodes for improving the performance of Li-S batteries. The mesoporous diameter of the ZnS nanosheets is approximately 10~30 nm and lots of pores in the 3D foams are observed. The porous structure provides abundant sites to adsorb and accommodate sulfur species. The cathode of the ZnS/r-GO/S exhibits 1259 mA h g⁻¹ of initial capacity and 971.9 mA h g⁻¹ of the reversible capacity after 200 cycles at 0.1 C (1 C = 1675 mA g⁻¹). At 1 C, it still exhibits the tiny capacity decay rate of 0.019% per cycle after 300 cycles. This work may be adopted to combine the nonpolar and polar materials as a 3D network structure for high-performance Li-S batteries.

Ammonia (NH₃) plays a key role in human society. The conventional Haber–Bosch process under high temperature and pressure is widely used to synthesize NH₃, resulting in huge energy costs and serious environmental issues. At present, the electrochemical conversion of nitrogen (N₂) and water (H₂O) into NH₃ at ambient conditions is considered as a promising and alternative method, and electrocatalysts are critical for nitrogen reduction reaction (NRR) to realize NH₃ synthesis. Graphene as an emerging 2D material has received significant attention in electrocatalysis NRR due to its unique properties such as high conductivity, specific surface area, a distinct 2D structure, and simplicity for modification. Herein, the electrochemical basis for NRR is provided including reactions in the NRR system, NRR mechanisms, criteria for NRR electrocatalysts (density functional theory and experiments), and verifying the nitrogen source and electrolytes. Then, the effect of doping (nonmetallic elements and single/dual metal atoms) and intrinsic defects on the NRR performance for graphene derivatives is reviewed, and the graphene composite electrocatalysts for NRR are summarized. Furthermore, deep sights and existing issues toward the further development of graphene derivatives and graphene composite electrocatalysts on NRR are discussed.