Boosting electrochemical wastewater-to- ammonia conversion via constructing TiO₂ Hybrid-nanostructure electrocatalyst
- 주제(키워드) TiO₂ , hybrid-nanostructure , nitrate reduction reaction , photo-nitrate reduction reaction , oxygen vacancy
- 주제(DDC) 621.042
- 발행기관 아주대학교 일반대학원
- 지도교수 조인선
- 발행년도 2024
- 학위수여년월 2024. 2
- 학위명 석사
- 학과 및 전공 일반대학원 에너지시스템학과
- 실제URI http://www.dcollection.net/handler/ajou/000000033472
- 본문언어 한국어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Ammonia has a substantial role in agriculture and the next generation of carbon-free energy supply. Electrochemical nitrate reduction into recyclable ammonium under benign conditions is significant. However, the development of such a process has been retarded by the lack of efficient electrocatalysts for highly selective synthesis of ammonia from wastewater. In this work, used to highly conductivity of carbon cloth as a substrate, morphology controlled of TiO₂ nanorods and hybrid nanostructure of nanorods with oxygen vacancies exhibit the microstructure characterization and surface defects and electrochemical charge dynamics characterization that compare with the nanoparticle. Herein, comparison wastewater to ammonia performance all samples, hybrid nanostructure of nanorod is showed to exhibit high faradaic efficiency (86.8 %) and selectivity (81.5 %) at - 0.6 V versus reversible hydrogen electrode from electrochemical nitrate reduction reaction and photoelectrochemical nitrate reduction reaction exhibit high faradaic efficiency (95.1 %) at - 0.5 V versus reversible hydrogen electrode in 0.1 M NaOH with 0.1 M NO₃-. Additionally, PEC-NO₃RR was conducted to confirm that light assists to produce ammonia yield and Faradaic efficiency.
more목차
1. Introduction 1
1.1 Necessity reducing of fossil fuel dependency 1
1.2 Ammonia (as a hydrogen carrier) 2
1.3 Ammonia production 4
1.4 Requirements of e-NO₃RR electrocatalysts 6
1.5 Electrode materials 8
1.5.1 Sol-gel method 8
1.5.2 Hydrothermal method 8
1.6 Titanium dioxide (TiO₂) 9
1.7 Research objective 11
2. Experimental 12
2.1 Material synthesis 12
2.1.1 Synthesis of TiO₂-seed 12
2.1.2 Synthesis of TiO₂-nanorods (NRs) 12
2.1.3 Synthesis of TiO₂-hybridnanorods (HNRs) 13
2.1.4 Synthesis of TiO₂ nanoparticles (NPs) 13
2.2 Material analysis 14
2.2.1 X-ray diffraction (XRD) 14
2.2.2 ¹H Nuclear Magnetic Resonance (¹H NMR) 14
2.3 Physical characterization 15
2.3.1 Scanning Electron Microscopy (SEM) 15
2.3.2 Transmission electron microscope (TEM) 15
2.4 Electrochemical analysis 16
2.4.1 (LSV, time-dependent chronoamperometry test) 16
2.4.2 Electrochemical impedance spectroscopy (EIS) 16
2.4.3 e-NO₃RR electrochemical measurements 17
2.5 Optical measurements 18
2.5.1 Raman spectroscopy 18
2.5.2 UV-visible Spectroscopy analysis (UV-vis) 18
2.5.3 Determination of NH₃-N 18
2.5.4 Determination of NO₂-N 19
2.5.5 Determination of NO₃-N 19
2.5.6 NO₃-N isotopic labelling experiment 19
2.5.7 Ammonia production and selectivity of equation 21
2.6 Material characterization 21
3. Results and discussion 22
3.1 Synthesis of TiO₂ hybrid nanorods (HNRs) on carbon cloth 22
3.2 Crystal and microstructure characterization 24
3.3 Surface defects and electrochemical charge dynamics characterization 26
3.4 Comparison wastewater to ammonia performance the different morphology of TiO₂ 29
3.5 e-NO₃RR performance of HNRs: selectivity & stability 31
3.6 PEC-NO₃RR performance of HNRs 33
4. Conclusion 35
5. Reference 36
국문요약 39
