Promoting electrochemical ammonia synthesis by synergized performances of Mo2C-Mo2N heterostructure

Tae-Yong An; Subramani Surendran; Sebastian Cyril Jesudass; Hyunjung Lee; Dae Jun Moon; Jung Kyu Kim; Uk Sim

doi:10.3389/fchem.2023.1122150

Promoting electrochemical ammonia synthesis by synergized performances of Mo₂C-Mo₂N heterostructure

Front Chem. 2023 Feb 16:11:1122150. doi: 10.3389/fchem.2023.1122150. eCollection 2023.

Authors

Tae-Yong An¹, Subramani Surendran¹, Sebastian Cyril Jesudass², Hyunjung Lee¹, Dae Jun Moon¹, Jung Kyu Kim³, Uk Sim^{1

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Affiliations

¹ Hydrogen Energy Technology Laboratory, Korea Institute of Energy Technology (KENTECH), Naju, Republic of Korea.
² Department of Science and Engineering, Chonnam National University, Gwangju, Republic of Korea.
³ School of Chemical Engineering, Sungkyunkwan University, Suwon, Republic of Korea.
⁴ Research Institute, NEEL Sciences, INC, Jeollanamdo, Republic of Korea.
⁵ Center for Energy Storage System, Chonnam National University, Gwangju, Republic of Korea.

Abstract

Hydrogen has become an indispensable aspect of sustainable energy resources due to depleting fossil fuels and increasing pollution. Since hydrogen storage and transport is a major hindrance to expanding its applicability, green ammonia produced by electrochemical method is sourced as an efficient hydrogen carrier. Several heterostructured electrocatalysts are designed to achieve significantly higher electrocatalytic nitrogen reduction (NRR) activity for electrochemical ammonia production. In this study, we controlled the nitrogen reduction performances of Mo₂C-Mo₂N heterostructure electrocatalyst prepared by a simple one pot synthesis method. The prepared Mo₂C-Mo₂N_0.92 heterostructure nanocomposites show clear phase formation for Mo₂C and Mo₂N_0.92, respectively. The prepared Mo₂C-Mo₂N_0.92 electrocatalysts deliver a maximum ammonia yield of about 9.6 μg h^-1 cm^-2 and a Faradaic efficiency (FE) of about 10.15%. The study reveals the improved nitrogen reduction performances of Mo₂C-Mo₂N_0.92 electrocatalysts due to the combined activity of the Mo₂C and Mo₂N_0.92 phases. In addition, the ammonia production from Mo₂C-Mo₂N_0.92 electrocatalysts is intended by the associative nitrogen reduction mechanism on Mo₂C phase and by Mars-van-Krevelen mechanism on Mo₂N_0.92 phase, respectively. This study suggests the importance of precisely tuning the electrocatalyst by heterostructure strategy to substantially achieve higher nitrogen reduction electrocatalytic activity.

Keywords: Mo2C catalyst; Mo2N catalyst; ammonia electrosynthesis; electrocatalyst; electrochemical nitrogen reduction reaction; heterostructures.

Grants and funding

This work was supported by the National Research Foundation of Korea grant funded by the Ministry of Science and the Korean Government (MSIT), Republic of Korea (NRF‐2021R1I1A1A01047527 and 2022R1A2C1012419) and New & Renewable Energy Core Technology Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) granted financial resource from Ministry of Trade, Industry and Energy, Republic of Korea (No. 20213030040590). This work was also supported by the KENTECH Research Grant funded by the Korea Institute of Energy Technology, Republic of Korea (KRG 2022–01–016). Following are results of a study on the “Leaders in INdustry-university Cooperation 3.0” Project, supported by the Ministry of Education and National Research Foundation of Korea. This work was also supported by Development of high-power capacitor (supercapacitor) performance enhancement technology customized for companies by the Ministry of Trade, Industry and Energy and Korea Evaluation Institute of Industrial Technology [Project No: 00155725/Project Name: Development of battery capacitors for long-term, high-capacity, and high power energy storage system.