Electrochemically converting nitrate, a widespread water pollutant, back to valuable ammonia is a green and delocalized route for ammonia synthesis, and can be an appealing and supplementary alternative to the Haber-Bosch process. However, as there are other nitrate reduction pathways present, selectively guiding the reaction pathway towards ammonia is currently challenged by the lack of efficient catalysts. Here we report a selective and active nitrate reduction to ammonia on Fe single atom catalyst, with a maximal ammonia Faradaic efficiency of ~ 75% and a yield rate of up to ~ 20,000 μg h−1 mgcat.−1 (0.46 mmol h−1 cm−2). Our Fe single atom catalyst can effectively prevent the N-N coupling step required for N2 due to the lack of neighboring metal sites, promoting ammonia product selectivity. Density functional theory calculations reveal the reaction mechanisms and the potential limiting steps for nitrate reduction on atomically dispersed Fe sites. Developing green and delocalized routes for ammonia synthesis is highly important but still very challenging. Here the authors report an efficient ammonia synthesis process via nitrate reduction to ammonia on Fe single atom catalyst.

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Electrochemical ammonia synthesis via nitrate reduction on Fe single atom catalyst.

Defect Engineering in Carbon‐Based Electrocatalysts: Insight into Intrinsic Carbon Defects

Various metal-based electrocatalysts from nanocrystals, to clusters and single-atoms, have been well-discovered towards high-efficient power devices and electrocatalytic conversion. To accelerate energy transformation materials discovery, developing high-throughput DFT calculations and machine-learning techniques is of great necessity. This review comprehensively outline the latest progress of theory-guided design of advanced energy transformation materials, especially, we focus on the study of single atoms in various power devices, such as fuel cell (oxygen reduction reaction, ORR; acid oxidation reaction; alcohol oxidation reaction), and other reactions for energy-related electrocatalytic conversion of small molecules, such as H2O2 evolution reactions (2e- ORR), water splitting (H2 evolution reaction/O2 evolution reaction, HER/OER), N2 reduction reaction (NRR), and CO2 reduction reactions (CO2RR). Firstly, the electronic structure, interaction mechanism, and reaction activation path are discussed to provide an overall blueprint in electrocatalysis and batteries mentioned above. Thereafter, the experimental synthesis strategies, structural recognition, and electrocatalytic performance for the advanced energy transformation materials are figured out. Finally, some viewpoints into the current issues and future design concept of the advanced energy transformation materials are provided.

Theory-oriented screening and discovery of advanced energy transformation materials in electrocatalysis

Various metal-based electrocatalysts from nanocrystals, to clusters and single-atoms, have been well-discovered towards high-efficient power devices and electrocatalytic conversion. To accelerate energy transformation materials discovery, developing high-throughput DFT calculations and machine-learning techniques is of great necessity. This review comprehensively outlines the latest progress of theory-guided design of advanced energy transformation materials. Especially, we focus on the study of single atoms in various power devices, such as fuel cell (oxygen reduction reaction, ORR; acid oxidation reaction; alcohol oxidation reaction), and other reactions for energy-related electrocatalytic conversion of small molecules, such as H 2 O 2 evolution reactions (2e − ORR), water splitting (H 2 evolution reaction/O 2 evolution reaction, HER/OER), N 2 reduction reaction (NRR), and CO 2 reduction reactions (CO 2 RR). Firstly, the electronic structure, interaction mechanism, and reaction activation path are discussed to provide an overall blueprint in electrocatalysis and batteries mentioned above. Thereafter, the experimental synthesis strategies, structural recognition, and electrocatalytic performance for the advanced energy transformation materials are figured out. Finally, some viewpoints into the current issues and future design concept of the advanced energy transformation materials are provided. 

Ammonia (NH3), one of the basic chemicals in most fertilizers and a promising carbon-free energy storage carrier, is typically synthesized via the Haber–Bosch process with high energy consumption a...

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Yuchi Wan

Papers

Heterogeneous electrocatalysts design for nitrogen reduction reaction under ambient conditions

Oxidation State Modulation of Bismuth for Efficient Electrocatalytic Nitrogen Reduction to Ammonia

Vanadium carbide with periodic anionic vacancies for effective electrocatalytic nitrogen reduction