Andac Armutlulu

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Armutlulu

First Name

Andac

ORCID

0000-0002-9084-8763

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Publications 1 - 10 of 30

CaO-Based CO2 Sorbents with a Hierarchical Porous Structure Made via Microfluidic Droplet Templating
Kurlov, Alexey; Armutlulu, Andac; Donat, Felix; et al. (2020)
Industrial & Engineering Chemistry Research
Visible-light-driven removal of atrazine by durable hollow core-shell TiO2@LaFeO3 heterojunction coupling with peroxymonosulfate via enhanced electron-transfer
Wei, Kexin; Armutlulu, Andac; Wang, Yinxu; et al. (2022)
Applied Catalysis B: Environmental
Insufficient charge-carriers separation and deteriorated recycling are still bottlenecks limiting practical photo-catalytic water purification. Herein, we developed a durable hollow core-shell TiO2@LaFeO3(TLFO) nanosphere via facile carbon-sphere-templated method and sol-gel process, and applied it as heterojunction photocatalyst coupled with peroxymonosulfate (PMS) for efficient atrazine (ATZ) removal via enhanced electron-transfer. The built-in electric field originated from the three-dimensional heterojunction between TiO2 and LaFeO3, acting as charge transfer driving force, enhanced the charge separation rate. Meanwhile, PMS could function as electron acceptor to boost photogenerated charge separation and maximize reactive oxidant species (e.g., (OH)-O-center dot, SO4 center dot-, O-2(center dot-) and O-1(2)) production. Therefore, the fabricated TLFO heterojunction exhibited outstanding reusability, and superior ATZ removal efficiency without detectable metal ion leaching. This work successfully demonstrates the synergistic effect and superior hollow structure of TLFO heterojunction with promoted light utilization and PMS activation, which offers potential application for efficient abating environmental pollution using solar energy.
Highly efficient removal of Cu(II) using mesoporous sodalite zeolite produced from industrial waste lithium-silicon-fume via reactive oxidation species route
Zhao, Dongping; Armutlulu, Andac; Chen, Yi; et al. (2021)
Journal of Cleaner Production
In this study, a low-cost mesoporous sodalite (SOD) zeolite was fabricated from industrial waste lithium-silicon-fume (LSF) using sodium salt-assisted alkaline desilication followed Vacuum Ultraviolet (VUV)-initiated ROS route. A highly crystallized mesoporous SOD zeolites can be obtained after merely 4 h VUV irradiation which exhibited superior ion-exchange capability with respect to Cu(II) (Qmax = 120.48 mg/g). The experimental and characterization results showed that the addition of sodium salt (i.e., Na2CO3 and NaHCO3) could greatly promote the dissolution of LSF, and induce development of mesoporous structures in zeolite without the requirement of template. The synthesized zeolite exhibited outstanding selectivity for Cu(II), which involved ion-exchange and hydroxyl complexation, and the spent zeolite after adsorbing Cu(II) can simply be regenerated by mild chemical washing. These results suggest sodium salt-assisted alkaline desilication followed Vacuum Ultraviolet (VUV) irradiation method is an effective way to fast turn solid waste into low-cost zeolites with superior ion-exchange capacity, which can be conductive to practical remediation of metal ion from wastewater.
Photoelectrochemical glycerol oxidation on Mo-BiVO4 photoanodes shows high photocharging current density and enhanced H2 evolution
Bora, Debajeet K.; Nadjafi, Manouchehr; Armutlulu, Andac; et al. (2022)
Energy Advances
Mo-doped BiVO4's lower efficiency can be attributed in part to exciton recombination losses. Recombination losses during photoelectrochemical water oxidation can be eliminated by using glycerol as a hole acceptor. This results in an enhanced photocurrent density. In this research, we present the synthesis of a Mo-doped BiVO4 photoelectrode with a greater photocurrent density than a traditional pristine photoanode system. Increased photon exposure duration in the presence of glycerol leads to 8 mA cm-2 increase in photocurrent density due to the creation of a capacitance layer and a decrease in charge transfer resistance on the photoelectrode in a neutral-phosphate buffer solution thus confirming the photo charging effect. Glycerol photooxidation improves the photoelectrode's rate of hydrogen evolution. Research into the effects of electrolyte and electrode potential on photoelectrodes has revealed that when the applied potential increases, the light absorbance behaviour changes following its absorption distribution over the applied potential. Under a transmission electron microscope (TEM), a unique dynamical crystal fringe pattern is found in the nanoparticles scratched from the photoelectrode.
Of Glasses and Crystals: Mitigating the Deactivation of CaO-Based CO₂ Sorbents through Calcium Aluminosilicates
Krödel, Maximilian; Leroy, César; Kim, Sung Min; et al. (2023)
JACS Au
CaO-based sorbents are cost-efficient materials for high-temperature CO₂ capture, yet they rapidly deactivate over carbonation-regeneration cycles due to sintering, hindering their utilization at the industrial scale. Morphological stabilizers such as Al₂O₃ or SiO₂ (e.g., introduced via impregnation) can improve sintering resistance, but the sorbents still deactivate through the formation of mixed oxide phases and phase segregation, rendering the stabilization inefficient. Here, we introduce a strategy to mitigate these deactivation mechanisms by applying (Al,Si)Oₓ overcoats via atomic layer deposition onto CaCO₃ nanoparticles and benchmark the CO₂ uptake of the resulting sorbent after 10 carbonation-regeneration cycles against sorbents with optimized overcoats of only alumina/silica (+25%) and unstabilized CaCO₃ nanoparticles (+55%). ²⁷Al and ²⁹Si NMR studies reveal that the improved CO₂ uptake and structural stability of sorbents with (Al,Si)Oₓ overcoats is linked to the formation of glassy calcium aluminosilicate phases (Ca,Al,Si)Oₓ that prevent sintering and phase segregation, probably due to a slower self-diffusion of cations in the glassy phases, reducing in turn the formation of CO₂ capture-inactive Ca-containing mixed oxides. This strategy provides a roadmap for the design of more efficient CaO-based sorbents using glassy stabilizers.
Constructing durable BiFeO3@SrBi2B2O7 p-n heterojunction for persulfate enhanced piezo-photocatalytic water purification
Wang, Yinxu; Chen, Jie; Wu, Jian; et al. (2023)
Separation and Purification Technology
Photoresponse piezoelectric materials have attracted tremendous interest as a new generation of photocatalysts for water purification. However, the development of durable and efficient piezo-photocatalyst remains to be a challenging task. Herein, a novel BiFeO3@SrBi2B2O7 (BFO@SBBO) p-n heterojunction with ultrahigh piezo-photocatalytic ability was fabricated after adjustment of BFO outer layer thickness, and utilized to activate persulfate (PS) for efficient water decontamination. The synergistic effect between the internal electric field across the heterojunction and the PS greatly improves the separation of photogenerated charge carriers. In the presence of ultrasonic mechanical vibration, 10 mg/L bisphenol A (BPA) was completely removed within 20 min with the assistance of a low dosage of PS upon visible light irradiation, which outperform various piezo-photocatalysts. Transformation and contribution of reactive oxygen species (ROSs, i.e., radical dotOH, O2radical dot−, 1O2 and SO4radical dot−) generated in the BFO@SBBO/US/Vis/PS system were evaluated and semi-quantified to understand the mechanism of BPA piezo-photocatalytic degradation. The stability and performance of BFO@SBBO piezo-photocatalysis toward typical organic pollutants and actual phenolic water remediation were evaluated, which confirmed the promising practical potential of BFO@SBBO in water remediation. This study offers a new insight into strategies for highly efficient piezo-photocatalyst for photocatalytic water remediation.
Operando X-ray Absorption Spectroscopy Identifies a Monoclinic ZrO2:In Solid Solution as the Active Phase for the Hydrogenation of CO2 to Methanol
Tsoukalou, Athanasia; Abdala, Paula Macarena; Armutlulu, Andac; et al. (2020)
ACS Catalysis
Operando X-ray absorption spectroscopy (XAS) associates the superior activity and stability of the In2O3/m-ZrO2 catalyst for the direct hydrogenation of CO2 to methanol (300 °C, 20 bar) to indium sites with an average oxidation state of +2.3 atomically dispersed in the lattice of monoclinic ZrO2. The active sites in this solid solution m-ZrO2:In catalyst are In–Vo–Zr sites (Vo is an oxygen vacancy) that are stabilized in the lattice of poorly reducible m-ZrO2 against deactivation by over-reduction to In0. In contrast, the amorphous ZrO2 support does not form a (crystalline) solid solution with In2O3 and, as a result, In2O3/am-ZrO2 reduces to metallic In within minutes under the reaction conditions. Furthermore, a tetragonal ZrO2 support stabilizes dispersed india nanocrystals (In2O3/t-ZrO2) against over-reduction only partially, yielding a catalyst with an average oxidation state of the In sites below +2: i.e., In2O3/t-ZrO2 also suffers deactivation by over-reduction. Our results demonstrate that the phase of the ZrO2 support determines whether an active solid solution with india forms, which has major implications for the reducibility of In3+ sites and their local structure. Comparing the stability and activity of india-based catalysts, we identified the monoclinic solid solution m-ZrO2:In as a superior catalyst for the direct conversion of CO2 to methanol, which contains active In–Vo–Zr surface species that are significantly more stable toward reduction than In–Vo–In sites in bixbyite-type In2O3.
Development of Coke-and sintering-resistant Ni/SiO2-based dry reforming catalyst by depositing a thin layer of AI2O3 via ALD
Kim, Sung Min; Armutlulu, Andac; Abdala, Paula M.; et al. (2017)
Development of an effective bi-functional Ni-CaO catalyst-sorbent for the sorption-enhanced water gas shift reaction through structural optimization and the controlled deposition of a stabilizer by atomic layer deposition
Kim, Sung Min; Armutlulu, Andac; Kierzkowska, Agnieszka M.; et al. (2020)
Sustainable Energy & Fuels
The integration of a CaO-based CO2 sorbent into catalytic schemes to remove CO2 from the product stream provides an effective means to reduce greenhouse gas emissions of chemical processes and to improve the yield and purity of the desired product. A key requirement for such so-called sorbent-enhanced processes is the availability of cyclically stable CO2 sorbent. To this end, we have developed CaO-based CO2 sorbents that combine favourable structural features and a high thermal stability by introducing a thin, conformal layer of Al2O3 (forming Ca3Al2O6 with CaO upon calcination) by atomic layer deposition. The structure and pore volume of the sorbent were found to play a key role in its CO2 capture. Functionalizing such CO2 sorbents with Ni nanoparticles yielded a highly effective bi-functional material for the sorption-enhanced water-gas shift (SE-WGS) reaction. The material showed a high yield of hydrogen of high purity and minimal CO slip over several cycles of repeated SE-WGS/regeneration operation.
Exsolution of Metallic Ru Nanoparticles from Defective, Fluorite-Type Solid Solutions Sm2RuxCe2–xO7 To Impart Stability on Dry Reforming Catalysts
Naeem, Muhammad A.; Abdala, Paula M.; Armutlulu, Andac; et al. (2020)
ACS Catalysis
A key challenge in the catalytic conversion of CH4 and CO2 into a synthesis gas (CO and H2) via the dry reforming of methane (DRM) is the development of stable catalysts. We demonstrate that the reductive exsolution of metallic Ru from fluorite-type solid solutions Sm2RuxCe2–xO7 (x = 0, 0.1, 0.2, 0.4) yields catalysts with high activity and remarkable stability for the DRM. The catalysts feature Ru(0) nanoparticles about 1–2 nm in diameter that are uniformly dispersed on the surface of the resulting oxide support. The exsolved material was investigated by synchrotron X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS at Ru, Sm, and Ce K-edges), Raman spectroscopy, and transmission electron microscopy. In situ XAS-XRD experiments revealed that the exsolution of metallic ruthenium is accompanied by a rearrangement of the oxygen vacancies within the lattice. The catalysts derived through exsolution outperform (stable over 4 days) the reference catalysts prepared by wetness impregnation and sodium borohydride reduction. The superior performance of the exsolved catalysts is explained by their high resistance to sintering-induced deactivation owing to the stabilizing metal–support interaction in this class of materials. It is also demonstrated that the Ru nanoparticles can undergo redissolution (in air at 700 °C)–exsolution cycles.

Publications 1 - 10 of 30

Andac Armutlulu

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