□ DGIST research team, led by Professor Sangaraju Shanmugam, Department of Energy Engineering, developed a catalyst that converts nitric oxide (NO) to ammonia (NH 3 ). This electrochemical technology offers high Faradaic efficiency [1] and low overpotential [2] and produces NH 3 in an eco-friendly manner.
□ NH 3 is an important chemical raw material in the fertilizer, textile, and pharmaceutical industries, and it is considered a carbon-free hydrogen carrier with a high energy density. Typically, NH 3 is produced using the Haber–Bosch process [3] ; however, this process is responsible for approximately 1–2% of global CO 2 emissions.
□ The electrochemical conversion of NO to NH 3 , an alternative to the Haber–Bosch process, has received considerable attention. This eco-friendly method consumes the air pollutant NO gas to produce NH 3 . Therefore, this promising approach can replace conventional methods without affecting the environment or emitting CO 2 .
□ However, owing to the corrosive nature of NO gas, the morphology of the metal-nanoparticle electrocatalyst degrades during electrosynthesis. Therefore, it is necessary to obtain a catalyst material with high stability that facilitates long-term electrochemical NH 3 synthesis.
□ Professor Shanmugam’ s research team developed a core-shell nickel nanoparticle coated with nitrogen-doped carbon nanostructured electrocatalysts via a simple co-precipitation method for stable NH 3 production. This catalyst is stable and efficient and offers a high Faradaic efficiency of 72.3% at a low overpotential (550 mV) in a 100% NO-saturated electrolyte. Additionally, a solar-to-NH 3 efficiency of 1.7% and Faradaic efficiency of more than 50% were achieved using a solar-energy-assisted full-cell PV-NORR electrolyzer.
□ Professor Shanmugam stated, “This research has developed an energy-efficient and eco-friendly technology to synthesize NH 3 with zero carbon footprint, and we hope to commercialize this technology to contribute to environmental conservation and sustainability.”
□ This mid-level research project was conducted with support from the Korean National Research Foundation (NRF). The findings of this research were published in Advanced Science , a renowned academic Journal in the field of materials engineering.
Correspondent author's e-mail address : sangarajus@dgist.ac.kr
[1] Faradaic efficiency: A measure of the efficiency with which the charge is consumed only for the given electrochemical reaction. A Faradaic efficiency of close to 100% indicates efficient charge consumption for the desired reaction.
[2] Overpotential: It indicates the potential difference between the thermodynamically determined potential of an electrochemical reaction and the potential at which the reaction is observed experimentally.
[3] Haber-Bosch Process: It is a process that can synthesize ammonia in large quantities from the abundant nitrogen in the air, and it triggered the agricultural revolution through the production of synthetic fertilizers using ammonia.
Advanced Science
Electrochemical Reduction of Nitric Oxide with 1.7% Solar-to-Ammonia Efficiency Over Nanostructured Core-Shell Catalyst at Low Overpotentials
18-Aug-2022