Synthesis, characterization, and catalytic evaluation of ni-supported fibrous zeolite y (Ni/FZY) for hydrogen production via glycerol dry reforming /
Nornasuha Abdullah,
Synthesis, characterization, and catalytic evaluation of ni-supported fibrous zeolite y (Ni/FZY) for hydrogen production via glycerol dry reforming / Nornasuha Abdullah - xviii, 196 pages : illustration ; 30 cm.+ 1 CD-ROM
Faculty of Chemical and Process Engineering Technology
Thesis (Doctor of Philosophy) -- Universiti Malaysia Pahang Al Sultan Abdullah - 2025
Include bibliographical reference
Glycerol dry reforming (GDR) is an eco-friendly method to convert glycerol, a biodiesel byproduct, and carbon dioxide (CO2) into hydrogen (H2). Nickel (Ni) catalysts are cost-effective but face deactivation from low basicity and metal particle sintering. This issue can be addressed by selecting an effective support material that minimizes coke formation and enhances stability. The study aims to develop a catalyst using Fibrous Zeolite Y (FZY) as a support for Ni loading to improve the catalytic performance and stability in GDR, addressing catalyst deactivation challenges. FZY was synthesized using a microemulsion method, resulting in spherical particles with a fibrous structure. By adjusting synthesis conditions (aging temperature, urea/TEOS ratio, and aging time), the FZY's surface area and pore structure were optimized. The best conditions were 100 °C aging temperature, 0.5 urea/TEOS ratio, and 4 h aging time as proven by the analysis results (BET, FTIR, TEM). Compared to conventional Zeolite Y (ZY), FZY had better access to active sites, a stronger structure, and higher thermal stability due to its radially arranged pores. When loaded with Ni, FZY significantly outperformed Ni/ZY in GDR, achieving 72.1 % glycerol conversion, 69.41 % H₂ yield, and 81.94 % CO yield. The fibrous structure improved Ni dispersion and reducibility, reducing coke buildup and boosting performance. This study investigated the influence of varying Ni loadings (15, 20, 25, and 30 %) on FZY for effective GDR. FESEM images revealed the most uniform dispersion in 20 Ni/FZY, while metal agglomeration was observed in 30 Ni/FZY. The optimal catalytic performance and stability of Ni/FZY were attained with a Ni loading of 20 wt%. This optimal performance was attributed to strong interactions between Ni and the support, moderate Ni particle size, and uniform distribution. Additionally, 20 Ni/FZY catalyst also had strong basicity and high oxygen vacancies, which improved active site accessibility and overall efficiency. The operational parameters for Ni/FZY in GDR were optimized using response surface methodology (RSM), followed by a stability assessment of the catalyst. Key process variables (F, C), including reaction temperature (F1, 600-900 °C), CO2/glycerol ratio (F2, 0.4-2), and gas hourly space velocity (F3, 15,000-32,000 mL/g⸱h), were investigated concerning glycerol conversion (C1) and H2 yield (C2). The optimal reaction conditions were determined to be F1 = 774 °C, F2 = 1.28, and F3 = 23,386.87 mL/g⸱h, with corresponding values of C1 = 83.57 % and C2 = 75.16 %. The synthesized Ni/FZY catalyst was demonstrated to exhibit significant stability over a time-on-stream (TOS) of 24 h. The proposed GDR mechanism involves the dissociative adsorption of glycerol and CO2 on the catalyst’s metallic sites, operating through a bifunctional pathway involving both basic and metallic active sites. The use of FZY as support was crucial, as its high surface area and strong basicity enhanced the catalytic activity of Ni, promoted uniform metal dispersion, and effectively suppressed carbon formation. Overall, Ni/FZY is a promising catalyst for clean hydrogen production, and future work should focus on scaling it up, using renewable energy, and further improving its design for industrial use.
THE0010330 (Local)
Faculty of Chemical and Process Engineering Technology--Dissertations
Universities and colleges--Dissertations
Synthesis, characterization, and catalytic evaluation of ni-supported fibrous zeolite y (Ni/FZY) for hydrogen production via glycerol dry reforming / Nornasuha Abdullah - xviii, 196 pages : illustration ; 30 cm.+ 1 CD-ROM
Faculty of Chemical and Process Engineering Technology
Thesis (Doctor of Philosophy) -- Universiti Malaysia Pahang Al Sultan Abdullah - 2025
Include bibliographical reference
Glycerol dry reforming (GDR) is an eco-friendly method to convert glycerol, a biodiesel byproduct, and carbon dioxide (CO2) into hydrogen (H2). Nickel (Ni) catalysts are cost-effective but face deactivation from low basicity and metal particle sintering. This issue can be addressed by selecting an effective support material that minimizes coke formation and enhances stability. The study aims to develop a catalyst using Fibrous Zeolite Y (FZY) as a support for Ni loading to improve the catalytic performance and stability in GDR, addressing catalyst deactivation challenges. FZY was synthesized using a microemulsion method, resulting in spherical particles with a fibrous structure. By adjusting synthesis conditions (aging temperature, urea/TEOS ratio, and aging time), the FZY's surface area and pore structure were optimized. The best conditions were 100 °C aging temperature, 0.5 urea/TEOS ratio, and 4 h aging time as proven by the analysis results (BET, FTIR, TEM). Compared to conventional Zeolite Y (ZY), FZY had better access to active sites, a stronger structure, and higher thermal stability due to its radially arranged pores. When loaded with Ni, FZY significantly outperformed Ni/ZY in GDR, achieving 72.1 % glycerol conversion, 69.41 % H₂ yield, and 81.94 % CO yield. The fibrous structure improved Ni dispersion and reducibility, reducing coke buildup and boosting performance. This study investigated the influence of varying Ni loadings (15, 20, 25, and 30 %) on FZY for effective GDR. FESEM images revealed the most uniform dispersion in 20 Ni/FZY, while metal agglomeration was observed in 30 Ni/FZY. The optimal catalytic performance and stability of Ni/FZY were attained with a Ni loading of 20 wt%. This optimal performance was attributed to strong interactions between Ni and the support, moderate Ni particle size, and uniform distribution. Additionally, 20 Ni/FZY catalyst also had strong basicity and high oxygen vacancies, which improved active site accessibility and overall efficiency. The operational parameters for Ni/FZY in GDR were optimized using response surface methodology (RSM), followed by a stability assessment of the catalyst. Key process variables (F, C), including reaction temperature (F1, 600-900 °C), CO2/glycerol ratio (F2, 0.4-2), and gas hourly space velocity (F3, 15,000-32,000 mL/g⸱h), were investigated concerning glycerol conversion (C1) and H2 yield (C2). The optimal reaction conditions were determined to be F1 = 774 °C, F2 = 1.28, and F3 = 23,386.87 mL/g⸱h, with corresponding values of C1 = 83.57 % and C2 = 75.16 %. The synthesized Ni/FZY catalyst was demonstrated to exhibit significant stability over a time-on-stream (TOS) of 24 h. The proposed GDR mechanism involves the dissociative adsorption of glycerol and CO2 on the catalyst’s metallic sites, operating through a bifunctional pathway involving both basic and metallic active sites. The use of FZY as support was crucial, as its high surface area and strong basicity enhanced the catalytic activity of Ni, promoted uniform metal dispersion, and effectively suppressed carbon formation. Overall, Ni/FZY is a promising catalyst for clean hydrogen production, and future work should focus on scaling it up, using renewable energy, and further improving its design for industrial use.
THE0010330 (Local)
Faculty of Chemical and Process Engineering Technology--Dissertations
Universities and colleges--Dissertations