Mass Transport Control by Surface Graphene Oxide for Selective CO Production from Electrochemical CO2 Reduction
- 주제(키워드) electrochemical CO2 reduction , suppression of H-2 evolution , Zn-based catalyst , reduced graphene oxide , computational fluid dynamics simulation
- 주제(기타) Chemistry, Physical
- 설명문(일반) [Dang Le Tri Nguyen; Lee, Chan Woo; Na, Jonggeol; Lee, Si Young; Sa, Young Jin; Won, Da Hye; Oh, Hyung-Suk; Lee, Ung; Hwang, Yun Jeong] KIST, Clean Energy Res Ctr, Seoul 02792, South Korea; [Min, Byoung Koun; Lee, Ung] Korea Univ, Green Sch, Seoul 02841, South Korea; [Dang Le Tri Nguyen; Nguyen Dien Kha Tu; Lee, Si Young; Oh, Hyung-Suk; Kim, Heesuk; Hwang, Yun Jeong] Korea Univ Sci & Technol UST, KIST Sch, Div Energy & Environm Technol, Seoul 02792, South Korea; [Hwang, Yun Jeong] Yonsei Univ, Yonsei KIST Convergence Res Inst, Dept Chem & Biomol Engn, Seoul 03722, South Korea; [Dang Le Tri Nguyen] Duy Tan Univ, Inst Res & Dev, Da Nang 550000, Vietnam; [Lee, Chan Woo] Kookmin Univ, Dept Chem, Seoul 02707, South Korea; [Kim, Min-Cheol; Han, Sang Soo] KIST, Computat Sci Res Ctr, Seoul 02792, South Korea; [Nguyen Dien Kha Tu; Kim, Heesuk] KIST, Photoelect Hybrids Res Ctr, Seoul 02792, South Korea; [Min, Byoung Koun] KIST, Natl Res Agenda Div, Seoul 02792, South Korea
- 관리정보기술 faculty
- 등재 SCIE, SCOPUS
- 발행기관 AMER CHEMICAL SOC
- 발행년도 2020
- URI http://www.dcollection.net/handler/ewha/000000172068
- 본문언어 영어
- Published As https://dx.doi.org/10.1021/acscatal.9b05096
초록/요약
Electrochemical CO2 reduction is always accompanied by a competitive hydrogen evolution reaction as water is used as a hydrogen source. In addition to intrinsic activity control, geometrical factors of electrocatalysts such as their porous structure have been demonstrated to affect the reaction selectivity, but understanding its origin is still important. Herein, we demonstrate that reduced graphene oxide layers can effectively control the Faradaic efficiency for CO production of porous zinc nanoparticle electrocatalysts. Simply tuning for CO production from 66 to 94% even in the bicarbonate electrolyte the coverage of graphene oxide dramatically varies Faradaic efficiency at the same biased potential, in which the hydrogen evolution rate was notably suppressed without sacrificing CO2 reduction to CO production rate unlike many Zn-based electrocatalysts. The graphene oxide layers are revealed to play roles in providing geometric barriers for the mass transport channels of reactants rather than changing the chemical states of the Zn-based electrocatalysts according to in situ X-ray absorption spectroscopic analysis and electrochemical reaction kinetic studies. In addition, computational fluid dynamics simulation studies estimate the Faradaic efficiency dependence on the surface coverage and suggest that the selective suppression of H-2 evolution is associated with the larger increment in local pH compared to that in local pCO(2) at the porous electrocatalyst surfaces. Decoupling between these reactant concentrations is originated from the higher consumption rate and lower bulk concentration of proton compared to those of CO2, and the surface coating with graphene oxide can be an effective way to control mass transport channel.
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