Electronic State Optimization for Electrochemical N2 Reduction Reaction in Aqueous Solution
Ammonia (NH3) is an important chemical to our human being and used in various areas, such as fertilizer for agriculture, feedstock for industries and carrier for hydrogen storage. However, the industrial NH3 production based on Harbor-Bosch (HB) method can only be done at high pressure and temperature with huge energy consumption, which makes the NH3 synthesis environmentally unsustainable. The NH3 synthesis by electrochemical N2 reduction reaction in mild aqueous solution (e-NRR) is attractive and meaningful to overcome the shortages of the HB method, where the electrocatalysts play critical role in the e-NRR efficiency. Especially, the electronic state is a crucial factor for electrocatalyst to be effective in e-NRR, which is mainly determined by the elemental composition. At the same time, the physical structures (such as special morphologies), hybridization, doping, and defects (such as vacancy) can further modify the electronic state of electrocatalyst, leading to ideally electrocatalytic activity for e-NRR. In this review, we summarize the strategies for the electronic state optimization at the key steps in e-NRR, such as N2 adsorption/activation, hydrogenation and hydrogen reaction route optimization. At the end of the review, suggestions to design novel electrocatalysts and outlooks for further improvement of their catalytic performances for e-NRR are highlighted.
- This article is part of the themed collection: Journal of Materials Chemistry A Recent Review Articles