Deciphering mass transport behavior in membrane electrode assembly by manipulating porous structures of atomically dispersed Metal-Nx catalysts for High-Efficiency electrochemical CO2 conversion

Seunghyun Lee, Ye Eun Jeon, Seonggyu Lee, Wonhee Lee, Seongbeen Kim, Jaeryung Choi, Jinkyu Park, Jeong Woo Han, You Na Ko, Young Eun Kim, Jinwon Park, Jungbae Kim, Ki Tae Park, Jinwoo Lee

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

The introduction of a porous structure is a promising approach to promote the electrochemical reaction of catalysts, which can maximize the utilization of catalytic active sites and enhance mass transport. To fully understand the role of the porous structure, parallel studies on both half-cell and full-cell environments must be performed; however, few studies have reported electrochemical CO2 conversion in a full-cell operation. In this work, we fabricated four types of porous Ni[sbnd]N[sbnd]C model catalysts designed to systematically investigate the relationship between porous structures and catalytic performances in a membrane electrode assembly (MEA) based catholyte-free CO2 electrolyzer. The performance degradation of the microporous catalyst in the MEA resulted from low CO2 accessibility due to small openings (<2 nm), and the absence of meso- or macropores that can facilitate mass transport in the catalyst layer. A thick catalyst layer developed a region in which H2 evolution was dominant; the formation of this region degraded the CO2 reduction efficiency in the MEA based on the macroporous catalyst. Consequently, mesoporous Ni-Nx catalysts with small, uniform particles exhibited the highest efficiency in MEAs, because their appropriate pore size and catalyst layer thickness facilitated mass transport. The optimized catalyst achieved industry-relevant performance for CO production (265 mA cm−2 at 2.3 V) with a state-of-the-art energy efficiency of 55 % and excellent long-term stability in a full cell.

Original languageEnglish
Article number142593
JournalChemical Engineering Journal
Volume464
DOIs
Publication statusPublished - 2023 May 15

Bibliographical note

Funding Information:
This work was partly supported by the Technology development Program of MSS (S3207729), a National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (Grant NRF-2020R1A2C3004146, 2019M3D1A1079306, 2020R1A2C3009649), and the framework of the research and development program of the Korea Institute of Energy Research (C2-2441).

Publisher Copyright:
© 2023 Elsevier B.V.

Keywords

  • Atomically dispersed metal catalyst
  • Electrocatalyst
  • Electrochemical CO reduction
  • Mesoporous material
  • Ni-N-C
  • Zero-gap electrolyzer

ASJC Scopus subject areas

  • General Chemistry
  • Environmental Chemistry
  • General Chemical Engineering
  • Industrial and Manufacturing Engineering

Fingerprint

Dive into the research topics of 'Deciphering mass transport behavior in membrane electrode assembly by manipulating porous structures of atomically dispersed Metal-Nx catalysts for High-Efficiency electrochemical CO2 conversion'. Together they form a unique fingerprint.

Cite this