Design of Single-Atom Catalysts for E lectrocatalytic Nitrogen Fixation

The Electrochemical nitrogen reduction reaction (ENRR) can be used to solve environmental problems as well as energy shortage. However, ENRR still faces the problems of low NH3 yield and low selectivity. The NH3 yield and selectivity in ENRR are affected by multiple factors such as electrolytic cells, electrolytes, and catalysts, etc. Among these catalysts are at the core of ENRR research. Single-atom catalysts (SACs) with intrinsic activity have become an emerging technology for numerous energy regeneration, including ENRR. In particular, regulating the microenvironment of SACs (hydrogen evolution reaction inhibition, carrier engineering, metal-carrier interaction, etc.) can break through the limitation of intrinsic activity of SACs. Therefore, this Review first introduces the basic principles of NRR and outlines the key factors affecting ENRR. Then a comprehensive summary is given of the progress of SACs (precious metals, non-precious metals, non-metallic) and diatomic catalysts (DACs) in ENRR. The impact of SACs microenvironmental regulation on ENRR is highlighted. Finally, further research directions for SACs in ENRR are discussed.

Promoting formation of oxygen vacancies in ceria multishelled hollow microspheres by doping iron for enhanced ambient ammonia electrosynthesis

Electrochemical nitrogen reduction reaction (NRR) is an environmentally friendly and sustainable approach for NH3 synthesis at mild pressure and temperature, but implementation depends on efficient electrocatalysts. Herein, iron-doped ceria multishelled...

Electrochemical reduction of nitrate on silver surface and the in situ Raman spectroscopy study

Electroreduction of nitrate to other essential fertilizer is becoming a crucial manner toward nitrate contamination treatment. In this report, Ag nanocrystals catalyst on quasi-cavity architecture of ZnO nanowalls has been...

Electrocatalytic N2 Reduction on FeS2 Nanoparticles Embedded in Graphene Oxide in Acid and Neutral Conditions

The development of stable, low-cost, and highly efficient electrocatalysts for the N₂ reduction reaction (NRR) process is challenging but crucial for ammonia production. Herein, we demonstrate the synthesis of pyrite nanoparticles wrapped by graphene oxide (FeS₂@GO) acting as a highly efficient NRR catalyst in a wide pH range. The FeS₂ nanoparticles are uniformly dispersed across the GO nanosheet, thus leading to the fine exposure of active sites, the promotion of charge transfer, and the increment of a contact surface area, which are all beneficial for a desired catalyst. In the meantime, the low-coordinated Fe atoms are activated as highly active sites, which is in favor of the enhanced electrochemical performance for the NRR. Furthermore, density functional theory (DFT) calculations illustrated that the high activity of N₂ reduction over the FeS₂@GO catalyst arises from the well-exposed Fe active sites and the increment of charge density at the valence band edge. Benefiting from the well-optimized interface, the barrier of the addition of the first hydrogen atom to N₂ forming *NNH species as the potential-determining step is as low as 0.93 eV in N₂ electroreduction. The electrochemical test results reveal that, as expected, FeS₂@GO exhibits high Faradaic efficiencies (4.7% in 0.1 M HCl solution and 6.8% in 0.1 M Na₂SO₄ solution) and advanced NH₃ yields (78.6 and 27.9 μg h^-1 mg_cat.^-1 in 0.1 M HCl and 0.1 M Na₂SO₄ solutions, respectively) in both acid and neutral conditions. This work offers a new avenue for exploring novel electrocatalysts, which has great promise to accelerate the practical application of the NRR.