This page has only limited features, please log in for full access.

Unclaimed
Abdulrhman Al-Awadi
Chemical Engineering Department, King Saud University, Riyadh 11421, Saudi Arabia

Basic Info

Basic Info is private.

Honors and Awards

The user has no records in this section


Career Timeline

The user has no records in this section.


Short Biography

The user biography is not available.
Following
Followers
Co Authors
The list of users this user is following is empty.
Following: 0 users

Feed

Journal article
Published: 18 May 2021 in Catalysts
Reads 0
Downloads 0

Chromium oxide supported on mesoporous organo-silica (MOS) was synthesized with different Cr loading by an incipient method. The catalytic performance of a Cr(x)/MOS catalyst for CO2-based ethane dehydrogenation was investigated. The synthesized catalysts were characterized by XRD, BET, TEM, SEM, XPS, FTIR, and UV–Vis DR measurements. The textural properties of the prepared samples showed that the mesoporous nature of MOS sample was not disturbed by chromium impregnation. Among the prepared samples, Cr(8)/MOS catalyst exhibited good distribution of chromium species along with superior concentration of Cr6+ and the highest recorded Cr6+/Cr3+ ratio. The results revealed that the superior catalytic performance was reached at Cr(8)/MOS, with 50.4% and 90.1% of ethane conversion and ethylene selectivity, respectively. The catalytic activity decreased slowly over reaction time; it declined approximately 22% after 10 h of stream operation. The roles of CO2-based ethane dehydrogenation were also studied, where carbon dioxide can be a source of lattice oxygen and as a hydrogen consumer in reverse water–gas shift (RWGS) reaction. The effect of various catalytic factors, such as catalytic temperature, reaction time, space gas velocity, and CO2 partial pressure on the conversion of ethane, yield, and selectivity to ethylene, were investigated as well.

ACS Style

Abdulrhman Al-Awadi; Ahmed El-Toni; Joselito Labis; Aslam Khan; Hamid Ghaithan; Attiyah Al-Zahrani; Ahmed Abasaeed; Saeed Al-Zahrani. Mesoporous Organo-Silica Supported Chromium Oxide Catalyst for Oxidative Dehydrogenation of Ethane to Ethylene with CO2. Catalysts 2021, 11, 642 .

AMA Style

Abdulrhman Al-Awadi, Ahmed El-Toni, Joselito Labis, Aslam Khan, Hamid Ghaithan, Attiyah Al-Zahrani, Ahmed Abasaeed, Saeed Al-Zahrani. Mesoporous Organo-Silica Supported Chromium Oxide Catalyst for Oxidative Dehydrogenation of Ethane to Ethylene with CO2. Catalysts. 2021; 11 (5):642.

Chicago/Turabian Style

Abdulrhman Al-Awadi; Ahmed El-Toni; Joselito Labis; Aslam Khan; Hamid Ghaithan; Attiyah Al-Zahrani; Ahmed Abasaeed; Saeed Al-Zahrani. 2021. "Mesoporous Organo-Silica Supported Chromium Oxide Catalyst for Oxidative Dehydrogenation of Ethane to Ethylene with CO2." Catalysts 11, no. 5: 642.

Journal article
Published: 20 November 2020 in Processes
Reads 0
Downloads 0

Nickel catalysts supported on zirconium oxide and modified by various amounts of lanthanum with 10, 15, and 20 wt.% were synthesized for CO2 reforming of methane. The effect of La2O3 as a promoter on the stability of the catalyst, the amount of carbon formed, and the ratio of H2 to CO were investigated. In this study, we observed that promoting the catalyst with La2O3 enhanced catalyst activities. The conversions of the feed, i.e., methane and carbon dioxide, were in the order 10La2O3 > 15La2O3 > 20La2O3 > 0La2O3, with the highest conversions being about 60% and 70% for both CH4 and CO2 respectively. Brunauer–Emmett–Teller (BET) analysis showed that the surface area of the catalysts decreased slightly with increasing La2O3 doping. We observed that 10% La2O3 doping had the highest specific surface area (21.6 m2/g) and the least for the un-promoted sample. The higher surface areas of the promoted samples relative to the reference catalyst is an indication of the concentration of the metals at the mouths of the pores of the support. XRD analysis identified the different phases available, which ranged from NiO species to the monoclinic and tetragonal phases of ZrO2. Temperature programmed reduction (TPR) analysis showed that the addition of La2O3 lowered the activation temperature needed for the promoted catalysts. The structural changes in the morphology of the fresh catalyst were revealed by microscopic analysis. The elemental compositions of the catalyst, synthesized through energy dispersive X-ray analysis, were virtually the same as the calculated amount used for the synthesis. The thermogravimetric analysis (TGA) of spent catalysts showed that the La2O3 loading of 10 wt.% contributed to the gasification of carbon deposits and hence gave about 1% weight-loss after a reaction time of 7.5 h at 700 °C.

ACS Style

Mahmud S. Lanre; Ahmed S. Al-Fatesh; Anis H. Fakeeha; Samsudeen O. Kasim; Ahmed A. Ibrahim; Abdulrahman S. Al-Awadi; Attiyah A. Al-Zahrani; Ahmed E. Abasaeed. Catalytic Performance of Lanthanum Promoted Ni/ZrO2 for Carbon Dioxide Reforming of Methane. Processes 2020, 8, 1502 .

AMA Style

Mahmud S. Lanre, Ahmed S. Al-Fatesh, Anis H. Fakeeha, Samsudeen O. Kasim, Ahmed A. Ibrahim, Abdulrahman S. Al-Awadi, Attiyah A. Al-Zahrani, Ahmed E. Abasaeed. Catalytic Performance of Lanthanum Promoted Ni/ZrO2 for Carbon Dioxide Reforming of Methane. Processes. 2020; 8 (11):1502.

Chicago/Turabian Style

Mahmud S. Lanre; Ahmed S. Al-Fatesh; Anis H. Fakeeha; Samsudeen O. Kasim; Ahmed A. Ibrahim; Abdulrahman S. Al-Awadi; Attiyah A. Al-Zahrani; Ahmed E. Abasaeed. 2020. "Catalytic Performance of Lanthanum Promoted Ni/ZrO2 for Carbon Dioxide Reforming of Methane." Processes 8, no. 11: 1502.

Journal article
Published: 16 July 2020 in Catalysts
Reads 0
Downloads 0

An environmentally-benign way of producing hydrogen is methane decomposition. This study focused on methane decomposition using Fe and Fe-Ni catalysts, which were dispersed over different supports by the wet-impregnation method. We observed the effect of modifying ZrO2 with La2O3 and WO3 in terms of H2 yield and carbon deposits. The modification led to a higher H2 yield in all cases and WO3-modified support gave the highest yield of about 90% and was stable throughout the reaction period. The reaction conditions were at 1 atm, 800 °C, and 4000 mL(hgcat)−1 space velocity. Adding Ni to Fe/x-ZrO2 gave a higher H2 yield and stability for ZrO2 and La2O3 + ZrO2-supported catalysts whose prior performances and stabilities were very poor. Catalyst samples were analyzed by characterization techniques like X-ray diffraction (XRD), nitrogen physisorption, temperature-programmed reduction (TPR), thermo-gravimetric analysis (TGA), and Raman spectroscopy. The phases of iron and the supports were identified using XRD while the BET revealed a significant decrease in the specific surface areas of fresh catalysts relative to supports. A progressive change in Fe’s oxidation state from Fe3+ to Fe0 was observed from the H2-TPR results. The carbon deposits on Fe/ZrO2 and Fe/La2O3 + ZrO2 are mainly amorphous, while Fe/WO3 + ZrO2 and Fe-Ni/x-ZrO2 are characterized by graphitic carbon.

ACS Style

Fahad Al-Mubaddel; Samsudeen Kasim; Ahmed A. Ibrahim; Abdulrhman S. Al-Awadi; Anis H. Fakeeha; Ahmed S. Al-Fatesh. H2 Production from Catalytic Methane Decomposition Using Fe/x-ZrO2 and Fe-Ni/(x-ZrO2) (x = 0, La2O3, WO3) Catalysts. Catalysts 2020, 10, 793 .

AMA Style

Fahad Al-Mubaddel, Samsudeen Kasim, Ahmed A. Ibrahim, Abdulrhman S. Al-Awadi, Anis H. Fakeeha, Ahmed S. Al-Fatesh. H2 Production from Catalytic Methane Decomposition Using Fe/x-ZrO2 and Fe-Ni/(x-ZrO2) (x = 0, La2O3, WO3) Catalysts. Catalysts. 2020; 10 (7):793.

Chicago/Turabian Style

Fahad Al-Mubaddel; Samsudeen Kasim; Ahmed A. Ibrahim; Abdulrhman S. Al-Awadi; Anis H. Fakeeha; Ahmed S. Al-Fatesh. 2020. "H2 Production from Catalytic Methane Decomposition Using Fe/x-ZrO2 and Fe-Ni/(x-ZrO2) (x = 0, La2O3, WO3) Catalysts." Catalysts 10, no. 7: 793.

Journal article
Published: 20 April 2020 in Crystals
Reads 0
Downloads 0

Ti modification of mesoporous silica support has been reported as an effective way to enhance Cr–Ti–Si interactions that, in turn, impact the catalytic dehydrogenation of ethane with CO2. However, such modification necessitates a repeated, time-consuming and tedious process. In this work, a simple, fast and facile approach has been utilized to synthesize chromium-oxide-loaded titania–silica mesoporous nanocomposites. A series of Cr(y)/Ti(x)–Si mesoporous nanocomposite catalysts with varying Ti and Cr contents were prepared and tested in the dehydrogenation of ethane with carbon dioxide. The as-synthesized catalysts were characterized by XRD, TEM, SEM, BET, UV–Vis–DR, XPS and H2–TPR techniques. The effect of titanium content, as well as chromium loading on the performance of the prepared Cr(y)/Ti(x)–Si catalysts, was investigated. It was found that 2.2 and 8 wt % are the optimum titanium and chromium contents in the synthesized catalysts for obtaining the highest catalytic activity. The superior catalytic performance of the Cr(8)/Ti(2.2)–Si catalyst can be attributed to a higher dispersion of the Cr species, as well as a higher content of the redox Cr species on the surface of the Cr/Ti–Si catalyst. The results showed that the Cr(8)/Ti(2.2)–Si catalyst efficiently dehydrogenated C2H6 in the presence of CO2 giving a 52.3% ethane conversion and 48.0% ethylene yield at 700 °C reaction temperature.

ACS Style

Abdulrhman S. Al-Awadi; Ahmed Mohamed El-Toni; Saeed M. Al-Zahrani; Ahmed E. Abasaeed; Aslam Khan. Synthesis, Characterization and Catalytic Evaluation of Chromium Oxide Deposited on Titania–Silica Mesoporous Nanocomposite for the Ethane Dehydrogenation with CO2. Crystals 2020, 10, 322 .

AMA Style

Abdulrhman S. Al-Awadi, Ahmed Mohamed El-Toni, Saeed M. Al-Zahrani, Ahmed E. Abasaeed, Aslam Khan. Synthesis, Characterization and Catalytic Evaluation of Chromium Oxide Deposited on Titania–Silica Mesoporous Nanocomposite for the Ethane Dehydrogenation with CO2. Crystals. 2020; 10 (4):322.

Chicago/Turabian Style

Abdulrhman S. Al-Awadi; Ahmed Mohamed El-Toni; Saeed M. Al-Zahrani; Ahmed E. Abasaeed; Aslam Khan. 2020. "Synthesis, Characterization and Catalytic Evaluation of Chromium Oxide Deposited on Titania–Silica Mesoporous Nanocomposite for the Ethane Dehydrogenation with CO2." Crystals 10, no. 4: 322.

Journal article
Published: 09 January 2020 in Catalysts
Reads 0
Downloads 0

A series of large-pore mesoporous silica (LPMS)-supported CrOx catalysts were synthesized by hydrothermal and impregnation methods and tested for ethane dehydrogenation in the presence of CO2 as an oxidant. To assess the effect of hydrothermal temperature treatment on the characteristics of LPMS support, different hydrothermal temperatures (100–160 °C) were studied and optimized. The optimum support was then loaded with different amounts of chromium (0, 2, 4, 8, and 11 wt % Cr). The obtained catalysts were characterized by different techniques such as XRD, BET, TEM, SEM, XPS, FTIR, and diffuse reflectance UV-Vis spectroscopy. The characterization results indicated that the sample hydrothermally treated at 130 °C exhibited the highest pore volume, a narrow pore size distribution, and a moderate BET surface area. Chromium species with various oxidation states including Cr3+, Cr6+, and α-Cr2O3 were detected in all synthesized Cr(y)/LPMS-130 catalysts. A lower Cr content resulted in the formation of Cr6+, whereas a higher Cr content dominated the α-Cr2O3 on the surface of the catalyst. Among the synthesized catalysts, the Cr(4)/LPMS-130 catalyst showed the highest Cr6+/Cr3+ ratio, indicating a good dispersion of chromium species along with a fine particle size. The ethane conversion and ethylene selectivity were 50.5 and 91.1% for Cr(4)/LPMS-130, respectively. Carbon dioxide was believed to supply enough lattice oxygen to maintain the Cr species at a higher oxidation state and to consume the hydrogen resulting from ethane cracking by a reverse water gas shift reaction.

ACS Style

Abdulrhman S. Al-Awadi; Saeed M. Al-Zahrani; Ahmed Mohamed El-Toni; Ahmed E. Abasaeed. Dehydrogenation of Ethane to Ethylene by CO2 over Highly Dispersed Cr on Large-Pore Mesoporous Silica Catalysts. Catalysts 2020, 10, 97 .

AMA Style

Abdulrhman S. Al-Awadi, Saeed M. Al-Zahrani, Ahmed Mohamed El-Toni, Ahmed E. Abasaeed. Dehydrogenation of Ethane to Ethylene by CO2 over Highly Dispersed Cr on Large-Pore Mesoporous Silica Catalysts. Catalysts. 2020; 10 (1):97.

Chicago/Turabian Style

Abdulrhman S. Al-Awadi; Saeed M. Al-Zahrani; Ahmed Mohamed El-Toni; Ahmed E. Abasaeed. 2020. "Dehydrogenation of Ethane to Ethylene by CO2 over Highly Dispersed Cr on Large-Pore Mesoporous Silica Catalysts." Catalysts 10, no. 1: 97.

Journal article
Published: 20 December 2019 in Crystals
Reads 0
Downloads 0

Oxidative dehydrogenation of alkanes to alkenes by a mild oxidant such as carbon dioxide is an active area of research. A series of MCM41-supported bimetallic oxide catalysts containing chromium oxide in addition to metal oxides (Ce, Co, Zn, V, Nb, and Mo) has been prepared. The binary catalysts have Cr metal oxide incorporated into MCM41 structure while the other oxides are either incorporated with Cr or impregnated on the MCM41 surface. The synthesized catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 sorption, scanning electron microscopy (SEM), hydrogen temperature programmed reduction (H2-TPR), and Diffuse reflectance UV–vis spectroscopy (DRS). The catalytic activity of Cr(4)-M(4)/MCM-41 catalysts in the dehydrogenation of ethane with CO2 was investigated. The textural properties of the synthesized samples showed that the addition of the bimetallic oxides did not disturb the mesoporous structure of MCM41 and the prepared catalysts exhibited a high BET surface area; however, the lowest surface area was recorded for Cr(4)-Mo(4)/MCM41 catalyst at 701 m2/g. Among the prepared catalysts, H2-TPR profile of Cr(4)-Ce(4)/MCM41 revealed the increase in the concentration of Cr6+ species which interacted with the framework of siliceous support. On the other hand, H2-TPR profiles of Cr(4)-Co(4)/MCM41 showed wide reduction peaks centered at 400 °C which is ascribed to reduction of Cr6+ to Cr3+ species and Co3O4 to metallic Co. At the same time, Cr(4)-Mo(4)/MCM41 and Cr(4)-V(4)/MCM41 exhibited higher temperature reduction peaks, indicating these two catalysts require higher activation temperatures. The synergy between the Cr with Zn or Nb metals reduced the concentration of Cr6+ species which is reflected in their catalytic performance. Cr(4)-Ce(4)/MCM41 recorded the highest catalytic activity toward ethylene production where the ethane conversion and ethylene yield were 37.9% and 35.1%, respectively.

ACS Style

Abdulrhman S. Al-Awadi; Ahmed Mohamed El-Toni; Mansour Alhoshan; Aslam Khan; Muhammad Ali Shar; Ahmed E. Abasaeed; Saeed M. Al-Zahrani. Synergetic Impact of Secondary Metal Oxides of Cr-M/MCM41 Catalyst Nanoparticles for Ethane Oxidative Dehydrogenation Using Carbon Dioxide. Crystals 2019, 10, 7 .

AMA Style

Abdulrhman S. Al-Awadi, Ahmed Mohamed El-Toni, Mansour Alhoshan, Aslam Khan, Muhammad Ali Shar, Ahmed E. Abasaeed, Saeed M. Al-Zahrani. Synergetic Impact of Secondary Metal Oxides of Cr-M/MCM41 Catalyst Nanoparticles for Ethane Oxidative Dehydrogenation Using Carbon Dioxide. Crystals. 2019; 10 (1):7.

Chicago/Turabian Style

Abdulrhman S. Al-Awadi; Ahmed Mohamed El-Toni; Mansour Alhoshan; Aslam Khan; Muhammad Ali Shar; Ahmed E. Abasaeed; Saeed M. Al-Zahrani. 2019. "Synergetic Impact of Secondary Metal Oxides of Cr-M/MCM41 Catalyst Nanoparticles for Ethane Oxidative Dehydrogenation Using Carbon Dioxide." Crystals 10, no. 1: 7.

Journal article
Published: 10 May 2019 in Applied Sciences
Reads 0
Downloads 0

Ni, Co, and Co–Ni bimetallic catalysts supported over SBA-15 and over SBA-15 doped with Zn or Ce oxides were prepared and tested in a methane dry reforming reaction. The loading of the metals in the catalyst was 5 wt % for either mono or bimetallic catalysts. The prepared catalysts were tested in a continuous-flow fixed-bed reactor at 800 °C under atmospheric pressure. XRD, TPR, TPD, and SEM characterization techniques were employed to investigate the catalytic properties of fresh catalysts. SEM and TGA were used to study the catalytic properties of spent catalysts. A remarkable effect on the reduction properties and catalytic performance of catalysts was observed after adding Zn and Ce. Over an 8 h test, Ni/SBA-15 showed the best activity and stability. The conversion was 90% for CH4 and CO2. Co–Ni/SBA-15 and Co–Ni/Ce–SBA-15 have shown a reasonable activity and stability. Selectivity of the Ni/SBA-15 catalyst was higher than all other catalysts as indicated by the H2/CO ratio. Co/SBA-15 and Co–Ni/Zn–SBA-15 showed a low activity and selectivity. TPD–NH3 profiles indicated that doping SBA-15 with Ce and/or Zn increased the catalyst acidic sites. Ni/SBA-15 is an excellent potential catalyst for commercial methane dry reforming processes.

ACS Style

Ahmed A. Ibrahim; Ashraf Amin; Ahmed S. Al-Fatesh; Nadavala Siva Kumar; Samsudeen Olajide Kasim; Abdulrhman S. Al-Awadi; Ahmed M. El-Toni; Ahmed Elhag Abasaeed; Anis H. Fakeeha. Nanosized Ni/SBA-15 Catalysts for CO2 Reforming of CH4. Applied Sciences 2019, 9, 1926 .

AMA Style

Ahmed A. Ibrahim, Ashraf Amin, Ahmed S. Al-Fatesh, Nadavala Siva Kumar, Samsudeen Olajide Kasim, Abdulrhman S. Al-Awadi, Ahmed M. El-Toni, Ahmed Elhag Abasaeed, Anis H. Fakeeha. Nanosized Ni/SBA-15 Catalysts for CO2 Reforming of CH4. Applied Sciences. 2019; 9 (9):1926.

Chicago/Turabian Style

Ahmed A. Ibrahim; Ashraf Amin; Ahmed S. Al-Fatesh; Nadavala Siva Kumar; Samsudeen Olajide Kasim; Abdulrhman S. Al-Awadi; Ahmed M. El-Toni; Ahmed Elhag Abasaeed; Anis H. Fakeeha. 2019. "Nanosized Ni/SBA-15 Catalysts for CO2 Reforming of CH4." Applied Sciences 9, no. 9: 1926.

Journal article
Published: 01 June 2018 in Catalysts
Reads 0
Downloads 0

The stability and catalytic activity of mesoporous Ni/MCM-41 promoted with a Ga loading of (0.0, 1.0, 1.5, 2.0, 2.5, and 3.0 wt %) as an innovative catalyst was examined for syngas production via CO2 reforming of CH4. The objective of present work was to develop a potential catalyst for CO2 reforming of methane. For this purpose different loadings of gallium were used to promote 5% nickel catalyst supported on MCM-41. An incipient wetness impregnation method was used for preparing the catalysts and investigated at 800 °C. Physicochemical characterization techniques—including BET, XRD, TPD, TPR, TEM, and TGA—were used to characterize the catalysts. The addition of small amounts of Ga resulted in higher surface areas with a maximum surface area of 1036 m2/g for 2.5% Ga. The incorporation of Ga to the catalyst decreased the medium and strong basic sites and reduced the amount of carbon deposited. There was no weight loss for 3%Ga+5%Ni/MCM-41. The 2% Ga loading showed the highest CH4 conversion of 88.2% and optimum stability, with an activity loss of only 1.58%. The Ga promoter raised the H2/CO ratio from 0.9 to unity.

ACS Style

Ahmed S. Al-Fatesh; Ahmed A. Ibrahim; Jehad K. Abu-Dahrieh; Abdulrahman S. Al-Awadi; Ahmed Mohamed El-Toni; Anis H. Fakeeha; Ahmed E. Abasaeed. Gallium-Promoted Ni Catalyst Supported on MCM-41 for Dry Reforming of Methane. Catalysts 2018, 8, 229 .

AMA Style

Ahmed S. Al-Fatesh, Ahmed A. Ibrahim, Jehad K. Abu-Dahrieh, Abdulrahman S. Al-Awadi, Ahmed Mohamed El-Toni, Anis H. Fakeeha, Ahmed E. Abasaeed. Gallium-Promoted Ni Catalyst Supported on MCM-41 for Dry Reforming of Methane. Catalysts. 2018; 8 (6):229.

Chicago/Turabian Style

Ahmed S. Al-Fatesh; Ahmed A. Ibrahim; Jehad K. Abu-Dahrieh; Abdulrahman S. Al-Awadi; Ahmed Mohamed El-Toni; Anis H. Fakeeha; Ahmed E. Abasaeed. 2018. "Gallium-Promoted Ni Catalyst Supported on MCM-41 for Dry Reforming of Methane." Catalysts 8, no. 6: 229.