Yazar "Yanalak, Gizem" seçeneğine göre listele

Listeleniyor 1 - 5 / 5
  • [ X ]
    Öğe
    Imidazole substituted Zinc(ii) phthalocyanines for co-catalyst-free photoelectrochemical and photocatalytic hydrogen evolution: influence of the anchoring group
    (Royal Soc Chemistry, 2021) Yuzer, A. Celil; Genc, Eminegul; Kurtay, Gulbin; Yanalak, Gizem; Aslan, Emre; Harputlu, Ersan; Ocakoglu, Kasim
    Novel zinc phthalocyanine derivatives, ZnPc-1 and ZnPc-2, consisting of one and four imidazole units, respectively, have been synthesized and utilized as panchromatic photosensitizers for photocatalytic and photoelectrochemical H-2 evolution. The effect of the imidazole-anchoring group on the photocatalytic H-2 production has been compared with ZnPc-3, which possesses a carboxylic acid unit as the anchoring group. ZnPc-1/TiO2 shows the best photoactivity with the highest H-2 evolution rate of 0.4006 mmol g(-1) h(-1), which is much higher than that of ZnPc-2/TiO2 and ZnPc-3/TiO2 (0.3319 mmol g(-1) h(-1) and 0.3555 mmol g(-1) h(-1), respectively). After 20 h of irradiation, ZnPc-1 produces an H-2 production rate of 3.4187 mmol g(-1) with a turnover number (TON) of 14863 and a solar-to-hydrogen energy (STH) conversion efficiency of 1.03%, without using a co-catalyst.
  • [ X ]
    Öğe
    Improving the Photocatalytic Hydrogen Generation Using Nonaggregated Zinc Phthalocyanines
    (Amer Chemical Soc, 2021) Acar, Eminegul Genc; Yuzer, A. Celil; Kurtay, Gulbin; Yanalak, Gizem; Harputlu, Ersan; Aslan, Emre; Ocakoglu, Kasim
    In comparison to traditional solar cells, the dye-sensitized photocatalytic system is one of the most appealing artificial photosynthesis mechanisms due to its low cost and straightforward fabrication. Herein, the photoelectrochemical and photocatalytic hydrogen evolution reactions of Zn-based phthalocyanine (Pc) derivatives, abbreviated as ZnPc-1 and ZnPc-2, were primarily studied in the presence of TEOA sacrificial electron donor. To this aim, the PC activities of ZnPc-1/TiO2 and ZnPc-2/TiO2 photocatalysts were investigated in the absence and presence of a cocatalyst. For the first hour, the amount of hydrogen generated by ZnPc derivatives (ZnPc-1/TiO2 and ZnPc-2/TiO2) was determined to be 1.221 and 0.864 mmol g(-1) h(-1), respectively. Additionally, the solar-to-hydrogen conversion efficiencies of ZnPc-1/TiO2 and ZnPc-2/TiO2 were ascertained to be 3.15% and 2.22%, respectively. Interestingly, STH efficiencies of photocatalysts were increased about 4-fold in the presence of a cocatalyst. Consequently, to elucidate the structural properties of ZnPc-1 and ZnPc-2, density functional theory (DFT) and time-dependent DFT studies were also conducted, and it was discovered that noncovalent interactions and steric hindrance effects on ZnPc-2 are tightly related to the experimentally determined PC activity differences between ZnPc-1 and ZnPc-2.
  • [ X ]
    Öğe
    Solar-light-driven photocatalytic hydrogen evolution by push-pull thiophenoxy-substituted zinc phthalocyanines
    (World Scientific Publ Co Pte Ltd, 2023) Acar, Eminegul Genc; Ince, Tuncay; Yuzer, A. Celil; Yanalak, Gizem; Gecgel, Cihan; Aslan, Emre; Ince, Mine
    Two zinc phthalocyanine derivatives (ZnPc 1 and 2) carrying bulky 2,6-diisopropylthiophenoxy peripheral substituents have been synthesized and their performances as photosensitizers in photochemical hydrogen production evaluated. To examine the influence of the spacer on the performance of ZnPc 1 and 2, the carboxyl group has been linked to the macrocycle ring either directly or via the phenyl ring, respectively. The photocatalytic activities of ZnPcs (ZnPc 1 and ZnPc 2) as sensitizers of TiO(2 )for hydrogen production were investigated in the presence of Pt. ZnPc 1 and ZnPc 2 sensitized TiO(2 )produced 0.687 mmolg(-1)h(-1) and 0.436 mmol g(-1)h(-1) hydrogens, which also reached 3.986 and 2.091 mmolg(-1) after 8h illumination, respectively, under visible light (>= 420 nm) irradiation. In addition, STH efficiencies of ZnPc 1/TiO2 and ZnPc 2/TiO2 were determined as 1.77% and 1.12%, respectively. ZnPc 1/TiO2 exhibited 1.9-fold more photocatalytic hydrogen amount than ZnPc 2/TiO2, and the hydrogen evolution performance of the photocatalyst in the presence of Pt enhanced to 3.021 mmol g(-1)h(-1) and 0.911mmol g(-1)h(-1) for ZnPc 1 and ZnPc 2, respectively.
  • [ X ]
    Öğe
    Subphthatocyanine-sensitized TiO2 photocatatyst for photoetectrochemical and photocatatytic hydrogen evolution
    (Royal Soc Chemistry, 2020) Yuzer, A. Celil; Genc, Eminegul; Harputlu, Ersan; Yanalak, Gizem; Aslan, Emre; Ocakoglu, Kasim; Patir, Imren Hatay
    A series of SubPcs comprising a carboxylic acid anchoring group at the peripheral (SubPcs 1, 2) or axial position (SubPc 3) were synthesized and used as sensitizers for photocatatytic H-2 production, for the first time. SubPc 3/TiO2 shows the best photocatatytic activity with a hydrogen evolution rate of 1396 mu mol h(-1), which is much higher than that of SubPcs 1 and 2 (771 and 658 mu mol g(-1) respectively). This work clearly shows that considering their optical and redox properties, SubPcs are promising candidates for light-driven water splitting systems.
  • [ X ]
    Öğe
    The effect of central metal in phthalocyanine for photocatalytic hydrogen evolution via artificial photosynthesis
    (Pergamon-Elsevier Science Ltd, 2020) Genc, Emineguel; Yuzer, A. Celil; Yanalak, Gizem; Harputlu, Ersan; Aslan, Emre; Ocakoglu, Kasim; Ince, Mine
    Phthalocyanines (Pcs) are promising sensitizers in photocatalytic hydrogen evolution reaction from water splitting owing to the unique absorption properties and familiar sensitizers for light phase of photosynthesis. In this paper, two phthalocyanines (Pcs) bearing tetra carboxylic acid at the peripheral position with Zn and Co atoms as a central metal have been prepared in order to investigate the effect of the central metal atoms on the performance of photocatalytic hydrogen evolution from water splitting for mimicking photosynthesis. The photoelectrochemical and photocatalytic hydrogen evolution ex-periments have been carried out by using Pcs sensitized TiO2 (TiO2, ZnPc/TiO2 and CoPc/TiO2) and Pt co catalyst in the presence of triethanolamine (TEOA) as a sacrificial electron donor under visible light. The hydrogen production rate of ZnPc/TiO2 and CoPc/TiO2 have been determined as the 1146 and 1051 mmolg(-1)h(-1), respectively. The hydrogen evolution rates of ZnPc/TiO2 and CoPc/TiO2 have been enhanced by in situ photodeposited Pt, which are reached by 3448 and 3328 mmolg(-1)h(-1) for the ZnPc/TiO2/Pt and CoPc/TiO2/Pt, respectively. These results have been established that ZnPc sensitized TiO2 shows more photocatalytic activity than CoPc sensitized TiO2 in the both absence and presence of Pt. These obtained results can be attributed to the spectral response of Pc sensitizers. (c) 2020 Elsevier Ltd. All rights reserved.