Manipulating wettability of catalytic surface for improving ammonia production from electrochemical nitrogen reduction

Dohun Kim; Khurshed Alam; Mi-Kyung Han; Subramani Surendran; Jaehyoung Lim; Joon Young Kim; Dae Jun Moon; Geonwoo Jeong; Myeong Gon Kim; Gibum Kwon; Sangsun Yang; Tae Gon Kang; Jung Kyu Kim; Seon Yeop Jung; Hoonsung Cho; Uk Sim

doi:10.1016/j.jcis.2022.11.052

Manipulating wettability of catalytic surface for improving ammonia production from electrochemical nitrogen reduction

J Colloid Interface Sci. 2023 Mar:633:53-59. doi: 10.1016/j.jcis.2022.11.052. Epub 2022 Nov 17.

Authors

Dohun Kim¹, Khurshed Alam¹, Mi-Kyung Han¹, Subramani Surendran², Jaehyoung Lim², Joon Young Kim³, Dae Jun Moon³, Geonwoo Jeong¹, Myeong Gon Kim¹, Gibum Kwon⁴, Sangsun Yang⁵, Tae Gon Kang⁶, Jung Kyu Kim⁷, Seon Yeop Jung⁸, Hoonsung Cho⁹, Uk Sim¹⁰

Affiliations

¹ Department of Materials Science & Engineering, Chonnam National University, Gwangju 61186, South Korea.
² Hydrogen Energy Technology Laboratory, Korea Institute of Energy Technology (KENTECH), 200 Hyeoksin-ro, Naju, Jeonnam 58330, Rep. of Korea.
³ Hydrogen Energy Technology Laboratory, Korea Institute of Energy Technology (KENTECH), 200 Hyeoksin-ro, Naju, Jeonnam 58330, Rep. of Korea; Research Institute, NEEL Sciences, INC., 58326 Jeollanamdo, South Korea.
⁴ Department of Mechanical Engineering, University of Kansas, Lawrence, KS 66045, United States.
⁵ Powder and Ceramics Division, Korea Institute of Materials Science, Changwon 51508, South Korea.
⁶ School of Aerospace and Mechanical Engineering, Korea Aerospace University, Goyang-si, Gyeonggi-do 10540, South Korea.
⁷ School of Chemical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 16419, Rep. of Korea.
⁸ Department of Chemical Engineering, Dankook University, Yongin-si, Gyeonggi-do 16890, South Korea. Electronic address: seon27@dankook.ac.kr.
⁹ Department of Materials Science & Engineering, Chonnam National University, Gwangju 61186, South Korea. Electronic address: cho.hoonsung@jnu.ac.kr.
¹⁰ Hydrogen Energy Technology Laboratory, Korea Institute of Energy Technology (KENTECH), 200 Hyeoksin-ro, Naju, Jeonnam 58330, Rep. of Korea; Research Institute, NEEL Sciences, INC., 58326 Jeollanamdo, South Korea; Center for Energy Storage System, Chonnam National University, Gwangju 61186, South Korea. Electronic address: usim@kentech.ac.kr.

PMID: 36434935
DOI: 10.1016/j.jcis.2022.11.052

Abstract

An electrochemical nitrogen reduction reaction (ENRR) is considered a promising alternative for the traditional Haber-Bosch process. In this study, we present a method for improving the ENRR by controlling the wettability of the catalyst surface, suppressing the hydrogen evolution reaction (HER) while facilitating N₂ adsorption. Reduced-graphene oxide (rGO) with a hydrophobic surface property and a contact angle (C.A.) of 59° was synthesized through a high-density atmospheric plasma deposition. Two other hydrophilic and superhydrophobic surfaces with a C.A. of 15° and 150° were developed through additional argon plasma and heat treatment of as-deposited rGO, respectively. The ENRR results showed that the ammonia yield and Faradaic efficiency tended to increase with increasing hydrophobicity. Electrochemical measurements reveal that superhydrophobic rGO achieves a higher Faradaic efficiency (5.73 %) at -0.1 V (vs RHE) and a higher NH₃ yield (9.77 μg h^-1 cm^-2) at -0.4 V (vs RHE) in a 0.1 M KOH electrolyte. In addition, the computational fluid dynamics simulation confirmed that the amount of time the N₂ gas remains on the surface could increase by improving the hydrophobicity of the catalytic surface. This study inspires the development of the rGO electrocatalyst through surface wettability modification for boosting ammonia electrosynthesis.

Keywords: Ammonia Electrosynthesis; Electrocatalyst; Electrochemical Nitrogen Reduction Reaction; Wettability; reduced-Graphene Oxide.

MeSH terms

Ammonia*
Graphite*
Nitrogen
Wettability

Substances

graphene oxide
Ammonia
Graphite
Nitrogen