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Concentration and pH Effects on Cu-Catalyzed Electrochemical CO₂ Reduction from First Principles Micro-Kinetic Modeling

Title
Concentration and pH Effects on Cu-Catalyzed Electrochemical CO₂ Reduction from First Principles Micro-Kinetic Modeling
Author(s)
Asghar Kamal
DGIST Authors
Asghar KamalYun Hee JangDae-Hyun Nam
Advisor
장윤희
Co-Advisor(s)
Dae-Hyun Nam
Issued Date
2022
Awarded Date
2022/08
Type
Thesis
Subject
Electrochemical CO2RR, Micro-Kinetic modeling, CatMAP, Partial Pressure , and pH Effect, Cu Catalyst, CORR
Description
Electrochemical CO2RR, Micro-Kinetic modeling, CatMAP, Partial Pressure , and pH Effect, Cu Catalyst, CORR
Abstract
ll the technologies we rely on in our lives are powered by fossil fuels. The con tinuous and extensive use of fossil fuels across the world releases billions of tons of CO2
into the atmosphere, which is connected to potential global warming. Therefore, the elec trochemical reduction of CO2 into valuable chemicals is one of the promising approaches
for the storage and conversion of sustainable energy. Herein, we present a refinement of a
previously developed microkinetic modeling approach1
that describes the CO2 reduction
(CO2RR) on copper at neutral and alkaline pH values towards mono carbon and multi carbon products for CO2 reduction reaction (CO2RR) on the surface of the Cu electrode.
Using the microkinetic modeling package CatMAP, we evaluated the turnover frequency
(TOF) of all products as a function of CO2 partial pressure and pH. We will show the
direct relationship among *CO-coverage, current density, reaction order (RO), and rate determining steps (RDS) of all products. Further, we bring here another issue that’s what
will be the effect of local CO partial pressure during the CO2RR? Because the produced
CO(g), during the CO2RR, is re-absorbed on the catalyst surface, giving the pathway for
the local-CORR. Hence, the second part of this work is to evaluate the effect of local CO
that happens as a result of the back reaction of CO, by fixing different CO2 partial pres sure, we evaluated the activity of the catalyst as a function of local CO partial pressure
and pH. Additionally, we have thrown a light on the comparative review of isolated CORR
with CO2RR. Therefore, this work will deliver some scientific conclusions that will help
to understand the role of CO2 partial pressure and pH in the microkinetic study of CO2RR.|우리가 삶에서 의존하는 거의 모든 기술은 화석 연료에 의해 구동됩니다. 전 세계적으로
화석 연료를 지속적으로 광범위하게 사용하면 수십억 톤의 CO2가 대기 중으로 방출되며
이는 잠재적인 지구 온난화와 연결됩니다. 따라서 CO2 의 가치 있는 화학 물질로의
전기화학적 환원은 지속 가능한 에너지의 저장 및 변환을 위한 유망한 접근 방식 중
하나입니다. 여기에서 중성 및 알칼리성 pH 값에서 구리에 대한 CO2 감소(CO2RR)를 단일
탄소 및 다중 탄소 제품에 대해 설명하는 이전에 개발된 미세 운동 모델링 접근법 의 개선
사항을 제시합니다. Cu 전극 표면의 CO2. 미세운동 모델링 패키지 CatMAP 을 사용하여
CO2분압 및 pH 의 함수로 모든 제품의 회전 빈도를 평가했습니다. 모든 제품의 *CO 범위,
전류 밀도, 반응 순서 및 속도 결정 단계 간의 직접적인 관계를 보여줍니다. 또한 CO2RR
동안 국부 CO 분압의 영향이 무엇인지에 대한 또 다른 문제를 여기에서 가져옵니다. CO2RR
동안 생성된 CO(g)가 촉매 표면에서 재흡수되어 국부 CORR 에 대한 경로를 제공하기
때문입니다. 따라서 이 연구의 두 번째 부분은 CO 의 역반응의 결과로 발생하는 국부적인
CO 의 영향을 평가하는 것입니다. 다른 CO2 분압을 고정하여 국부적 인 함수로 촉매의
활성을 평가했습니다. CO 분압 및 pH. 또한 CO2RR 이 있는 격리된 CORR 의 비교 검토에
대해 조명했습니다. 따라서 이 작업은 CO2RR 의 미세 운동 연구에서 CO2 분압과 pH 의
역할을 이해하는 데 도움이 되는 몇 가지 과학적 결론을 제공할 것입니다.
Table Of Contents
2 Introduction 1
2.1 Fossil Fuel Reliance and Rising CO2 Levels: 1
2.2 Recycling CO2: 2
2.3 Challenges in CO2RR: 2
2.4 Kinetic Aspect of CO2RR: 3
2.5 Hydrogen Evolution Reaction: 4
2.6 Butler-Volmer Equation: 5
2.7 Thesis Objectives: 5
3 Methodology 7
3.1 Computational Framework and Micro-Kinetic Modeling: 7
3.2 Catalysis Microanalysis Package (CatMAP) and Kinetics: 8
3.2.1 CatMAP: 10
3.2.1.1 Generating an Input File: 10
3.2.1.2 Creating a Microkinetic Model: 11
3.2.1.3 Refining a Microkinetic Model: 12
3.2.1.4 Output Variables: 12
4 Results and Discussion 14
4.1 CO2RR Model: 14
4.1.1 Reaction Mechanism: 14
4.1.2 CO Coverage Under CO2RR: 15
4.1.3 Voltage-Current Profile: 18
4.1.4 Rate Limiting Step: 19
4.1.5 Adsorbate-adsorbate Interaction: 20
4.1.6 CO2RR as a Function of Partial pressure and pH: 22
4.1.6.1 Partial Pressure Dependent CO2RR: 28
4.1.6.2 pH Dependent CO2RR: 29
4.1.6.3 Quantification of Reaction Order: 30
4.2 Microkinetic Modeling of CO2RR Using Local pCO as a New Variable (Local CORR Model): 32
4.3 A Comparative Review of CORR Model: 36
4.4 HER Model Under CO2RR, local CORR, and Isolated CORR: 46
5 Conclusion and Future Plan: 49
URI
http://dgist.dcollection.net/common/orgView/200000630353

http://hdl.handle.net/20.500.11750/16797
DOI
10.22677/thesis.200000630353
Degree
Master
Department
Department of Energy Science and Engineering
Publisher
DGIST
Related Researcher
  • 장윤희 Jang, Yun Hee
  • Research Interests Multiscale molecular modeling (quantum mechanics calculation; molecular dynamics simulation) : Supercomputer-assisted molecular-level understanding of materials and their chemistry; which leads to rational design of high-performance organic-inorganic-hybrid materials for clean and renewable energy as well as low-energy-consumption electronic devices
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