Development of Carbon‐Based Electrocatalysts for Ambient Nitrogen Reduction Reaction: Challenges and Perspectives

Abstract

Ammonia is an important chemical and a potential carbon-free hydrogen-storage material. Currently, the industrial synthesis of ammonia is mainly achieved via the Haber-Bosch method, which requires high energy, temperatures, and pressures. An alternative method involves the electrocatalytic nitrogen reduction reaction (NRR), which uses an aqueous solution as a medium and requires mild reaction conditions. The key to the NRR is to select an appropriate catalyst to increase the ammonia yield and Faradic efficiency. With their diverse structures and easy regulation, carbon-based materials can provide abundant active sites for nitrogen absorption and excitation. Moreover, they are abundant, low cost, and readily available, making them promising for use in NRR applications. Accordingly, we review the latest progress in using carbonbased materials in the NRR, and the future development prospects of NRR catalysts are discussed. Finally, challenges and perspectives of the future research of NRR catalysts are provided.

Ammonia Energy: Synthesis and Utilization

“…48,49 Doping with heteroatoms is the most practical method to improve the efficiency of NRR catalysts. 50 According to the type of heteroatom, it is generally divided into two types: metal doping and nonmetal doping. By introducing heteroatoms, the NRR reaction barrier can be effectively reduced and the number of active sites can be increased.…”

Selective Electrochemical Conversion of N2 to NH3 in Neutral Media Using B, N-Containing Carbon with a Nanotubular Morphology

“…To accomplish this, the electrocatalyst should have the ability to reduce N 2 at a reduced overpotential as well as suppress competing HER to obtain a high Faradic efficiency (F.E.) and NH 3 production yield rate. , To date, a number of sophisticated electrocatalysts have been reported to bring about selective N 2 reduction, including transition-metal-based and metal-free carbon-based catalysts. − N-doped carbon materials have sparked universal attention as they modify the electronic properties of the carbon catalyst and facilitate selective N 2 adsorption . Numerous works have been performed to boost the kinetics of NRR by N-doped carbons, while the poor Faradic efficiency and yield rate obstruct the practical applicability.…”

Flower-Like Ni–Mn Bimetallic Oxide-Based Nanosheets for Enhanced Electrocatalytic Nitrogen Reduction to Ammonia

“…Currently, there is an urgent need for a more energy-saving and efficient method of synthesizing ammonia that can utilize renewable energy while reducing CO 2 emissions. , Therefore, green and sustainable nitrogen fixation methods have attracted much attention. Among them, electrochemical nitrogen reduction reaction ( e -NRR) is expected to replace the conventional Haber–Bosch process as an environmentally friendly and sustainable NH 3 synthesis method. , In the e -NRR system, aqueous solution is used as a proton donor instead of fossil fuels and the entire electrolysis reaction occurs under ambient conditions, avoiding harsh high-temperature and high-pressure reaction conditions. − The dissolution, adsorption, activation, and inevitable competitive reaction between nitrogen and the hydrogen evolution reaction (HER) lead to the current ammonia yield and Faraday efficiency being still in the initial stage, far from reaching the level of mass production . The core of research on improving the performance of electrocatalytic nitrogen reduction for ammonia synthesis is the rational design of efficient electrocatalysts, which can improve the reaction rate and ammonia selectivity by promoting the activation of N 2 and allowing more active sites to be occupied by N atoms. − …”