In article number 1800337, Liang-Xin Ding, Haihui Wang, and co-workers review current strategies to address the selectivity challenges for electrochemical nitrogen reduction reaction (NRR). The proposed strategies are systematically summarized from the perspective of catalyst design, cell configuration, electrolyte choice etc. Moreover, as a new field, a standard pattern for executing control experiments is recommended. This review gives further insights about NRR studies.

This review summarizes current strategies for tackling the selectivity challenge of electrocatalytic nitrogen reduction reaction (NRR). The proposed strategies from the perspectives of catalyst design, cell configuration, electrolyte choice, etc., are systematically researched. To ensure experimental rigor, a standard pattern for executing control experiments is recommended. This review is expected to motivate the NRR field toward greater advancement.

This review focuses on the defect engineering strategies to design highly efficient electrochemical or photocatalytic nitrogen reduction reaction (NRR) nanocatalysts. The defect sites would serve as the active sites for NRR and further enhance its intrinsic performance. The defect engineering strategies are summarized in different categories, including vacancies, doping, amorphous phases, size effect, and structure effect.

Photochemical synthesis via nitrogen reduction reaction has gained increased attention as a sustainable method for the production of ammonia. This review discusses the basic understanding of photoreduction of nitrogen and highlights the development of photocatalysts and photoelectrocatalysts for ammonia synthesis. The methods for ammonia detection are also introduced.

Nitrogen reduction under mild conditions has been developed rapidly in recent years. Here, the fundamental mechanisms behind the reported cases together with the designing rules for electrocatalytic and photocatalytic nitrogen fixation toward efficient nitrogen reduction are discussed.

S-doped carbon nanospheres (S-CNSs) are an efficient catalyst for electrochemical N₂ fixation to NH₃. In 0.1 m Na₂SO₄, the S-CNS attains a large NH₃ yield of 19.07 µg h⁻¹ mg⁻¹_cat. and a high Faradic efficiency of 7.47% at –0.7 V vs RHE. Notably, this catalyst demonstrates high electrochemical and structure stabilty.

Partially oxidized chromium nitride (chromium oxynitride) nanoparticles are synthesized and their nitrogen reduction reaction activities are evaluated in a proton exchange membrane electrolyzer under ambient conditions. The highest ammonia formation rate of 8.9 × 10⁻¹¹ mol s⁻¹ cm⁻² and Faradaic efficiency of 6.7% are achieved at 2.0 and 1.8 V, respectively.

Non-noble metal semiconductor BiVO₄ along with different oxygen vacancies (OVs) concentrations is obtained by a facile hydrothermal synthesis. Based on the theoretical calculations, the optimum BiVO₄ (pH = 7) sample presents brilliant N₂ reduction reaction electrocatalytic performance under ambient conditions owing to the enhanced N₂ adsorption energy and more favorable active reaction site at the V atom due to the introduction of OVs.

Among various N₂ electroreduction methods, combining N₂ reduction with batteries is simple and efficient. Here, a composite of ultrasmall Mo₂C particles dispersed on N-doped carbon nanosheets acts as the air cathode for Li–N₂ batteries. With high discharge capacity and superior reversibility, the Li–N₂ battery is a promising platform for N₂ electroreduction and electrochemical energy storage.

NbO₂ nanoparticles are successfully prepared and demonstrated as an efficient electrocatalyst for N₂ fixation, with a peak faradaic efficiency of 32% at −0.60 V versus reversible hydrogen electrode. Compared to the Nb⁵⁺ counterpart, Nb⁴⁺ not only provides empty d-orbitals but also d-electrons to enable π back donation, and thus exhibits better electrocatalytic N₂ reduction activity.

Double atomic catalysts will become the altar of atomic catalysts for nitrogen reduction reaction instead of single atomic catalysts. Moreover, the Mn₂-C₂N has the highest catalytic activity with the potential of −0.23 V versus reversible hydrogen electrode, indicating the promising catalyst for practical applications.

One major challenge for electrochemical nitrogen reduction is the competition from hydrogen evolution. Herein, is reported the development of a microkinetic model that includes both competing reactions and mass transport. The simulation results suggest the possibility that proton transfer becomes rate-limiting in nitrogen reduction and microstructured electrodes may pose a negative effect on selectivity due to poor mass transport.

Critical roles of anchoring and peripheral ligand in N₂ reduction are investigated theoretically based on the trigonal bipyramidal (XP^iPr ₃)Fe (X = B, C, N) scaffold. Increasing the electron-donating ability of anchor atom (X) facilitates N₂ activation and protonation. Tuning the redox ligands is proposed as a promising direction toward better catalysts for N₂ fixation.

Searching for highly efficient and stable electrocatalysts for N₂ fixation is critical to NH₃ synthesis. Here, it is proposed that a single tungsten atom anchored on g-C₃N₄ exhibits superior catalytic performance for N₂ reduction to NH₃ due to its low limiting potential, significant suppressing effect for HER, and good stability.