MINISTRY OF EDUCATION AND TRANING HANOI UNIVERSITY OF SCIENCE AND TECHNOLOGY DOAN ANH TUAN Synthesis of Cu-Fe/SAPO-34 catalysts for the selective catalytic reduction (SCR) of NOx with NH3 CHEMICAL ENGINEERING DOCTORAL DISSERTATION Hanoi – 2022 luan an MINISTRY OF EDUCATION AND TRANING HANOI UNIVERSITY OF SCIENCE AND TECHNOLOGY DOAN ANH TUAN Synthesis of Cu-Fe/SAPO-34 catalysts for the selective catalytic reduction (SCR) of NOx with NH3 Major: Chemical Engineering Code No: 9520301 CHEMICAL ENGINEERING DOCTORAL DISSERTATION ADVISORS: 1. Pham Thanh Huyen 2. Le Minh Thang Hanoi – 2022 luan an STATUTORY DECLARATION I hereby declare that I myself have written this thesis book. The data and results presented in the dissertation are true and have not been published by other authors.
Hanoi, 07th January 2022 ADVISORS: PhD Student 1. Pham Thanh Huyen Doan Anh Tuan 2. Le Minh Thang i luan an ACKNOWLEDGEMENT First and foremost, undoubtedly, I must give gratitude to my advisor, Assoc. Pham Thanh Huyen, for giving me the opportunity to work under her supervision for the last four years.
She provided patience, encouragement, and advice, which is necessary for me to proceed through the PhD program and complete the thesis. I would like to thank Prof. Le Minh Thang for her from-time-to-time encouragement. She has been a strong supervisor to me throughout my school years at HUST, but she has always given me sufficient freedom to carry out independent work.
At the same time, I also want to thank Dr. Vuong Thanh Huyen for her support, great contribution and feedbacks on the publications and dissertation. I would like to acknowledge Prof. Angelika Brückner and Dr.
Jabor Rabeah for helpful guidance, the experience shared, and discussions during my research at Leibniz Institute for Catalysis (University of Rostock, Germany). Further thank goes to Dr. Stephan Bartling for the XPS measurements and useful ideas, Dr. Henrik Lund for the XRD measurements and valuable comments.
Additionally, I would like to send appreciations to Mr. Reinhard Eckelt for BET measurements, Mrs. Anja Simmula for the ICP-OES measurements. I would like to acknowledge the RoHan Project for the financial and equipments support during my stage.
A special thank goes to Dr. Dirk Hollmann and Dr. Esteban Mejia who have been very supportive in every way. And I also would like to thank the Vingroup Innovation Foudation (VINIF) Funding for financial support.
Last but not least, I would like to thank my friends at Hanoi University of Science and Technology and at Leibniz Institute for Catalysis for all assistances and for the enjoyable time, friendly events we shared together. Finally, I would like to express my deepest appreciation to my family and my love for all their love, patience, encouragement, and unconditional support throughout my life including the years of PhD studying. ii luan an TABLE OF CONTENT STATUTORY DECLARATION i ACKNOWLEDGEMENT ii TABLE OF CONTENT iii LIST OF ABBREVIATIONS vi LIST OF FIGURES viii LIST OF TABLES xii INTRODUCTION 1 THE NEW CONTRIBUTION OF THE DESSERTATION 4 CHAPTER 1. STATE OF THE ART 6 1.
Nitrogen oxides emission and abatement 6 1. Selective catalytic reduction of NOx with NH3 10 1. Overview of the selective catalytic reduction technology 10 1. The mechanism of NH3-SCR 12 1.
Catalysts for NH3-SCR of NOx 14 1. Effect of other components in NH3-SCR of NOx 17 1. Inhibition of water vapor 17 1. Poisoning by sulfur dioxide 17 1.
Poisoning by alkali metals 18 1. Zeolite and silicoaluminophosphate materials 18 1. Overview of zeolite materials 18 1. Overview of silicoaluminophosphate materials 20 1.
Catalysts selection for NH3-SCR of NOx 24 1. Supports selection for NH3-SCR of NOx 24 1. Metal-exchange selection for NH3-SCR of NOx 30 1. Iron species as active sites 30 1.
Copper species as active sites 32 1. Multimetallic species as active sites 33 iii luan an 1. Scope of the dissertation 34 CHAPTER 2. Synthesis of SAPO-34 support 36 2.
Preparation of metal/zeolite catalysts 37 2. NH3-SCR activity test of catalysts 38 2. Catalyst characterization methods 40 2. The X-ray diffraction spectroscopy 40 2.
Inductively coupled plasma - optical emission spectrometry 42 2. Flame atomic absorption spectrometry 42 2. Field emission scanning electron microscopy and energy dispersive X-ray spectroscopy 42 2. Brunauer – Emmett – Teller surface area analysis 43 2.
Fourier transformed infrared spectroscopy 44 2. Chemisorption temperature-programmed 46 2. Solid-state nuclear magnetic resonance spectroscopy 46 2. UV-Vis diffuse reflectance spectroscopy 47 2.
X-ray photoelectron spectroscopy 48 2. Electron paramagnetic resonance 48 CHAPTER 3. RESULTS AND DISCUSSION 53 3.1 The influence of OSDAs on the formation of SAPO-34 structure 53 3.2 The influence of silicon sources for SAPO-34 formation 63 3.3 Copper-iron bimetal ion-exchanged SAPO-34 for NH3-SCR of NOx 71 3. Structure and texture of catalysts 71 3.
Redox and acid properties results 75 3. Cu and Fe species onto SAPO-34 78 3. A comparison catalysts performance between metals-based SAPO- 34 and metals-based ZSM-5 89 3. The stability of SAPO-34 based catalysts 98 3.
Influence of hydrothermal aging on activity 98 iv luan an 3. Water vapor and SO2 poisoning resistance 99 3. Structure-reactivity relationships and active sites 102 3. in-situ EPR investigations 102 3.
in-situ FT-IR investigations 107 3. Proposal NH3-SCR mechanism over Cu-Fe/SAPO-34 catalyst 111 GENERAL CONCLUSIONS AND OUTLOOK 115 PUBLICATIONS OF THE DISSERTATION 117 REFERENCES 120 APPENDIX A A1 APPENDIX B A6 APPENDIX C A12 APPENDIX D A17 v luan an LIST OF ABBREVIATIONS AlPO4 Aluminophosphates BET Brunauer – Emmett – Teller CHA Chabazite D6R Double 6‐membered rings DEA Diethylamine DOC Diesel oxidation catalyst DPF Diesel particulate filter EDS Energy-dispersive X-ray spectroscopy EPR Electron paramagnetic resonance E-R Eley-Rideal EU European Union FAAS Flame atomic absorption spectrometry FE-SEM Field emission scanning electron microscope FT-IR Fourier transformed infrared spectroscopy GHSV Gas hourly space velocity H2-SCR Selective catalytic reduction by hydrogen H2-TPR The temperature-programmed reduction with H2 HCs-SCR Selective catalytic reduction by hydrocarbons ICP-OES Inductively coupled plasma optical emission spectrometry IUPAC International Union of Pure and Applied Chemistry L-H Langmuir-Hinshelwood Mor Morpholine MR Membered rings MTO Methanol to light olefins NH3-SCR Selective catalytic reduction by ammonia or urea NH3-TPD Temperature-programmed desorption with ammonia NMR Nuclear magnetic resonance NOx Nitrogen oxides OSDAs Organic structure-directing agents ppm Parts per million SAPOs Silicoaluminophosphates SBUs Secondary building units SCR Selective catalytic reduction TEA Triethylamine vi luan an TEAOH Tetraethylammonium hydroxide TEOS Tetraethyl orthosilicate TEPA Tetraethylenepentamine UV-Vis DRS Ultraviolet – visible diffuse reflectance spectroscopy vol.% Volume percentage w/w Weight by weight wt.% Weight percentage XPS X-ray photoelectron spectroscopy XRD X-ray diffraction ZSM-5 Zeolite Socony Mobil–5 vii luan an LIST OF FIGURES Figure 1. Schematics of atmospheric NOx reactions 7 Figure 1. The emission of NOx in the EU from different sector groups 9 Figure 1.
Concept of installing urea tanks in heavy duty vehicles 11 Figure 1. A schematic diagram of SCR reaction following E-R mechanism (left), L-H mechanism (right) 13 Figure 1. NH3-SCR reaction process over iron-exchanged zeolites according to Brandenberger et al. The developed zeolite-based catalysts with various topology structures for NH3-SCR 16 Figure 1.
Three steps of the sulfate deposition and the corresponding methods for the restriction of the negative effects of the SO2 poisoning 18 Figure 1. Schematic of zeolites Brønsted acid site 19 Figure 1. Schematic formation of AlPO4 21 Figure 1. A planar schematic of silicon incorporation mechanisms in an AlPO4 framework 22 Figure 1.
Brønsted acidity in zeolite and SAPOs 23 Figure 1. Framework of MFI projected along [010] and an illustration of the molecular channels and cages for the 10MR opening 25 Figure 1. Framework of CHA projected along [010] and illustration of the molecular channels and cages for 8MR pore opening 26 Figure 1. Possible iron species present as active sites Fe-zeolites for NH3-SCR 31 Figure 1.
Possible cation positions in the CHA structure 32 Figure 1. Proposed reaction mechanism of NH3-SCR reaction over Cu- zeolites 33 Figure 2. Experimental diagram for preparation of SAPO-34 support 36 Figure 2. Experimental diagram for preparation catalysts 38 Figure 2.
Schematic diagram of NH3-SCR experimental apparatus 39 Figure 2. A scheme set up of the water evaporation for the experiments of the effect of the water 40 Figure 2. a) The diffraction of the X-ray beam on the planes of the crystalline of the solid, b) the principle of the X-ray powder diffraction 41 Figure 2. a) BET isotherm (red) compares to Langmuir isotherm (blue), b) Visualization of BET 44 viii luan an Figure 2.
The scheme of in-situ FT-IR experiments set up 45 Figure 2. Illustration of the Zeeman splitting for a S = 1/2 system with one unpaired electron in an external magnetic field B0 49 Figure 2. a) CW EPR spectrum for an axially elongated copper complex; b) same spectrum drawn as absorption spectrum with a 2D plot 50 Figure 2. Scheme of the in-situ EPR experiment set up 51 Figure 3.
XRD diffraction pattern of as-synthesized samples 53 Figure 3. FE-SEM images of as-synthesized samples 55 Figure 3. FT-IR spectra of all samples with a full range of wavelength 58 Figure 3. N2 adsorption and desorption isotherms of as-synthesized samples 59 Figure 3.
NH3-TPD profiles of as-synthesized samples 60 Figure 3. 29Si MAS NMR spectrum of all samples 61 Figure 3. X-ray diffraction patterns of as-synthesized samples 64 Figure 3. FE-SEM images of as-synthesized samples 65 Figure 3.
N2 adsorption and desorption isotherms of S08 and S12 samples 67 Figure 3. NH3‐TPD pattern of samples 68 Figure 3. 29Si MAS NMR spectrum of S08 and S12 samples 70 Figure 3. XRD patterns of as-synthesized SAPO-34 and catalysts 71 Figure 3.
N2 adsorption-desorption isotherms of as-synthesized samples 73 Figure 3. FE-SEM images of all catalysts 74 Figure 3. Temperature-programmed desorption of NH3 as-synthesized samples 76 Figure 3. H2-TPR profiles of catalyst samples 77 Figure 3.
UV–Vis DRS spectra of the catalyst samples 79 Figure 3. XPS results of O 1s of all catalysts 80 Figure 3. XPS results of Fe 2p of 1Fe/SAPO-34 and 3Cu-1Fe/SAPO-34 81 Figure 3. XPS results of Cu 2p of 3Cu/SAPO-34 and 3Cu-1Fe/SAPO-34 82 Figure 3.
EPR spectra of catalysts measured at room temperature 84 Figure 3. a) Conversion of NOx and b) selectivity of N2 and N2O concentration during standard NH3-SCR of Cu/SAPO-34 catalysts 85 Figure 3. a) Conversion of NOx and b) selectivity of N2 and N2O concentration during standard NH3-SCR of Fe/SAPO-34 catalysts 86 Figure 3. a) Conversion of NOx and b) selectivity of N2 and N2O concentration during standard NH3-SCR of Cu-Fe/SAPO-34 catalysts 87 ix luan an Figure 3.
a) Comparison conversion of NOx during the standard NH3- SCR and b) NH3 conversion during the NH3 oxidation experiment of 3Cu/SAPO-34, 3Fe/SAPO-34 and 3Cu-1Fe/SAPO-34 88 Figure 3. XRD patterns of ZSM-5 and as-synthesized catalysts 90 Figure 3. FE-SEM images of all catalysts 91 Figure 3. N2 adsorption and desorption isotherms of catalysts 92 Figure 3.
EPR spectra of catalysts measured at room temperature 93 Figure 3. a) Conversion of NOx and b) selectivity of N2 and N2O concentration during standard NH3-SCR of Cu/ZSM-5 catalysts 94 Figure 3. a) Conversion of NOx and b) selectivity of N2 and N2O concentration during standard NH3-SCR of Fe/ZSM-5 catalysts 95 Figure 3. a) Conversion of NOx and b) selectivity of N2 and N2O concentration during standard NH3-SCR of Cu-Fe/ZSM-5 catalysts 95 Figure 3.
NOx conversions versus temperatures over metals-based ZSM- 5 (dash line) and metals-based SAPO-34 (straight line) 97 Figure 3. a) NOx conversion of Cu/SAPO-34 and Cu-Fe/SAPO-34 after hydrothermal aging with GHSV of 120000 h-1 and (b) XRD patterns of fresh and hydrothermal aging catalysts 99 Figure 3. NOx conversion over Cu/SAPO-34, Fe/SAPO-34 and Cu- Fe/SAPO-34 catalysts at 200 °C under GHSV of 70000 h-1 in the co- presence of H2O + SO2 100 Figure 3. NOx conversion over Cu/SAPO-34, Fe/SAPO-34 and Cu- Fe/SAPO-34 catalysts at 300 °C under GHSV of 70000 h-1 in the co- presence of H2O + SO2 101 Figure 3.
in-situ EPR spectra of a) Cu/SAPO-34 and b) Cu-Fe/SAPO-34 after NH3/He/NO+O2 adsorption at 200 °C 103 Figure 3. Skeleton structure diagram of the unit cell of SAPO-34.