Dang Le Tri Nguyen Lee, Chan Woo Na, Jonggeol Kim, Min-Cheol Nguyen Dien Kha Tu Lee, Si Young Sa, Young Jin Won, Da Hye Oh, Hyung-Suk Kim, Heesuk Min, Byoung Koun Han, Sang Soo Lee, Ung Hwang, Yun Jeong 2024-01-19T18:01:47Z 2024-01-19T18:01:47Z 2021-09-05 2020-03-06 2155-5435 https://pubs.kist.re.kr/handle/201004/118860 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. English AMER CHEMICAL SOC OXIDATION-STATE HIGHLY EFFICIENT ZN NANOSHEETS ELECTROREDUCTION CATALYSTS ELECTROCATALYST NANOPARTICLES CHALLENGES MORPHOLOGY SYNGAS Mass Transport Control by Surface Graphene Oxide for Selective CO Production from Electrochemical CO2 Reduction Article 10.1021/acscatal.9b05096 1 ACS CATALYSIS, v.10, no.5, pp.3222 - 3231 ACS CATALYSIS 10 5 3222 3231 scie scopus 000518876300034 2-s2.0-85080039854 Chemistry, Physical Chemistry Article OXIDATION-STATE HIGHLY EFFICIENT ZN NANOSHEETS ELECTROREDUCTION CATALYSTS ELECTROCATALYST NANOPARTICLES CHALLENGES MORPHOLOGY SYNGAS electrochemical CO2 reduction suppression of H-2 evolution Zn-based catalyst reduced graphene oxide computational fluid dynamics simulation