Advances in Electrocatalytic N₂ Reduction—Strategies to Tackle the Selectivity Challenge

Abstract

The industrial process used to reduce N 2 to NH 3 , typically the Haber-Bosch process, is energy-intensive and highly dependent on fossil fuels, a major source of greenhouse gas emissions causing undesirable climate change. Electrochemical reduction of N 2 to NH 3 using renewable energy is one attractive approach to address this problem. A major challenge for electrochemical nitrogen reduction reaction (NRR) is low catalytic activity, accompanied by ultralow selectivity. Current studies have made some breakthroughs in Faradaic efficiency, with reasonable current density, while remaining far from satisfying the needs of commercial applications. This review discusses current strategies, focusing on the perspectives of catalyst design, cell configuration, electrolyte choice, etc., to tackle the selectivity challenge. In addition, rigorous control experiments to eliminate possible ammonia contamination and standard ammonia detection methods to ensure data accuracy are proposed, providing guidance for the field of NRR studies. , he continued his studies there as a postdoctoral fellow in 2005. Now he is a full professor at the South China University of Technology, China. His interests focus on inorganic membranes, membrane reactor, and energy materials.

Oxygen Vacancy–Enhanced Electrocatalytic Performances of TiO2 Nanosheets toward N2 Reduction Reaction

“…Interfaces 2019, 6,1901034 working electrode was prepared by dropping 28 µL of the prepared ink solution on the carbon substrate and dried naturally. Mater.…”

“…[2] This harsh condition is obviously energy consuming and accompanies a large amount of CO 2 output, bringing a serious global warming problem. [6] It has been extensively reported that heterogenous catalysts play vital roles in breaking or lowing the energy barrier required in the rate-determining step in electroreduction from N 2 to NH 3 , [7] which is the key in further improving N 2 reduction reaction (NRR) performances. [3][4][5] Among them, N 2 electroreduction is considered as the most promising and environmentally benign way because the electricity utilized during the catalysis can be produced by some renewable sources, such as solar and wind energy.…”

“…Interfaces 2019,6, 1901034 The absorption intensity becomes high when the OV-TiO 2 -300 sample serves as the catalysts and reaches the highest for OV-TiO 2 -400 electrocatalysts.…”

“…Interfaces 2019,6, 1901034 the FE are shown inFigure 4a. b) Absorption spectra of the electrolyte with the existence of indophenol indicator after NRR tests at various applied potential for OV-TiO 2 -400 electrocatalysts.…”

Enhanced Electrocatalytic N2 Reduction via Partial Anion Substitution in Titanium Oxide–Carbon Composites

“…[3] In aqueous solution, the increase of the electric potential to enhance the activation of N 2 is an option of limited applicability as NRR under these conditions is largely inhibited by the competitive hydrogen evolution reaction (HER). [5] Until now, various promising catalysts have been investigated for electrochemical NRR, including metals, [6] metal oxides, [7] metal nitrides, [8] metal carbides, [9] metal complexes [10] and carbon-based materials. Theu ltimate requirement to such types of catalysts is to bind and polarize N 2 molecules in away that the electron density within the molecule is shifted to facilitate the reaction with protons and/or electrons.…”