Remarkable enhancement of photocatalytic hydrogen evolution efficiency utilizing an internal cavity of supramolecular porphyrin hexagonal nanocylinders under visible-light irradiation

Taku Hasobe; Hayato Sakai; Kentaro Mase; Kei Ohkubo; Shunichi Fukuzumi

doi:10.1021/jp400381h

Remarkable enhancement of photocatalytic hydrogen evolution efficiency utilizing an internal cavity of supramolecular porphyrin hexagonal nanocylinders under visible-light irradiation

Taku Hasobe, Hayato Sakai, Kentaro Mase, Kei Ohkubo, Shunichi Fukuzumi

Department of Chemistry & Nanoscience

Research output: Contribution to journal › Article › peer-review

42 Scopus citations

Abstract

An efficient visible light-induced hydrogen evolution system has been developed by using supramolecular porphyrin hexagonal nanocylinders that encapsulate Pt-colloids-deposited TiO₂ nanoparticles (Pt/TiO ₂) in the internal cavity. First, porphyrin nanocylinders structurally controlled by encapsulated Pt/TiO₂ are prepared via a solvent mixture technique. The bar-shaped structure composed of Pt/TiO ₂ and zinc meso-tetra(4-pyridyl)porphyrin [ZnP(Py)₄] is formed with the aid of a surfactant: cetyltrimethylammonium bromide (CTAB) in a DMF/H₂O mixture solution [denoted as Pt/TiO₂-ZnP(Py) ₄ nanorods]. In scanning electron microscopy (SEM) measurements, ZnP(Py)₄ pristine hexagonal nanocylinder with a large hollow structure [denoted as ZnP(Py)₄ nanocylinder] was observed, whereas the hollow hole was completely closed in case of Pt/TiO₂-ZnP(Py) ₄ nanorods. X-ray diffraction (XRD) analyses also revealed that ZnP(Py)₄ alignment in the nanorod was based on the stacked-assemblies of ZnP(Py)₄ coordinated hexagonal formations. These results clearly indicate that Pt colloids-deposited TiO₂ nanoparticles (Pt/TiO ₂) were successfully encapsulated within a ZnP(Py)₄ hexagonal nanocylinder. Pt/TiO₂-ZnP(Py)₄ also shows a broadened absorption in the visible region because of aggregation of ZnP(Py)₄. Then, Pt/TiO₂-ZnP(Py)₄ exhibited efficient hydrogen evolution under visible light irradiation, whereas no hydrogen was evolved in the case of Pt/TiO₂ without ZnP(Py) ₄. In addition, the hydrogen evolution efficiency of Pt/TiO ₂-ZnP(Py)₄ nanorods per unit weight of Pt was two orders magnitude greater than that of the nonencapsulated system: Pt/TiO₂ and ZnP(Py)₄ nanocylinder composites [Pt/TiO₂ + ZnP(Py)₄ composites]. Finally, the photodynamics of the excited state of Pt/TiO₂-ZnP(Py)₄ nanorods was examined by femtosecond time-resolved transient absorption spectroscopy to clarify the photocatalytic mechanism.

Original language	English
Pages (from-to)	4441-4449
Number of pages	9
Journal	Journal of Physical Chemistry C
Volume	117
Issue number	9
DOIs	https://doi.org/10.1021/jp400381h
State	Published - 7 Mar 2013

Access to Document

10.1021/jp400381h

Cite this

@article{91463fb927ba42fd9535902b3eb66c51,

title = "Remarkable enhancement of photocatalytic hydrogen evolution efficiency utilizing an internal cavity of supramolecular porphyrin hexagonal nanocylinders under visible-light irradiation",

abstract = "An efficient visible light-induced hydrogen evolution system has been developed by using supramolecular porphyrin hexagonal nanocylinders that encapsulate Pt-colloids-deposited TiO2 nanoparticles (Pt/TiO 2) in the internal cavity. First, porphyrin nanocylinders structurally controlled by encapsulated Pt/TiO2 are prepared via a solvent mixture technique. The bar-shaped structure composed of Pt/TiO 2 and zinc meso-tetra(4-pyridyl)porphyrin [ZnP(Py)4] is formed with the aid of a surfactant: cetyltrimethylammonium bromide (CTAB) in a DMF/H2O mixture solution [denoted as Pt/TiO2-ZnP(Py) 4 nanorods]. In scanning electron microscopy (SEM) measurements, ZnP(Py)4 pristine hexagonal nanocylinder with a large hollow structure [denoted as ZnP(Py)4 nanocylinder] was observed, whereas the hollow hole was completely closed in case of Pt/TiO2-ZnP(Py) 4 nanorods. X-ray diffraction (XRD) analyses also revealed that ZnP(Py)4 alignment in the nanorod was based on the stacked-assemblies of ZnP(Py)4 coordinated hexagonal formations. These results clearly indicate that Pt colloids-deposited TiO2 nanoparticles (Pt/TiO 2) were successfully encapsulated within a ZnP(Py)4 hexagonal nanocylinder. Pt/TiO2-ZnP(Py)4 also shows a broadened absorption in the visible region because of aggregation of ZnP(Py)4. Then, Pt/TiO2-ZnP(Py)4 exhibited efficient hydrogen evolution under visible light irradiation, whereas no hydrogen was evolved in the case of Pt/TiO2 without ZnP(Py) 4. In addition, the hydrogen evolution efficiency of Pt/TiO 2-ZnP(Py)4 nanorods per unit weight of Pt was two orders magnitude greater than that of the nonencapsulated system: Pt/TiO2 and ZnP(Py)4 nanocylinder composites [Pt/TiO2 + ZnP(Py)4 composites]. Finally, the photodynamics of the excited state of Pt/TiO2-ZnP(Py)4 nanorods was examined by femtosecond time-resolved transient absorption spectroscopy to clarify the photocatalytic mechanism.",

author = "Taku Hasobe and Hayato Sakai and Kentaro Mase and Kei Ohkubo and Shunichi Fukuzumi",

year = "2013",

month = mar,

day = "7",

doi = "10.1021/jp400381h",

language = "English",

volume = "117",

pages = "4441--4449",

journal = "Journal of Physical Chemistry C",

issn = "1932-7447",

publisher = "American Chemical Society",

number = "9",

}

Remarkable enhancement of photocatalytic hydrogen evolution efficiency utilizing an internal cavity of supramolecular porphyrin hexagonal nanocylinders under visible-light irradiation. / Hasobe, Taku; Sakai, Hayato; Mase, Kentaro et al.
In: Journal of Physical Chemistry C, Vol. 117, No. 9, 07.03.2013, p. 4441-4449.

Research output: Contribution to journal › Article › peer-review

TY - JOUR

T1 - Remarkable enhancement of photocatalytic hydrogen evolution efficiency utilizing an internal cavity of supramolecular porphyrin hexagonal nanocylinders under visible-light irradiation

AU - Hasobe, Taku

AU - Sakai, Hayato

AU - Mase, Kentaro

AU - Ohkubo, Kei

AU - Fukuzumi, Shunichi

PY - 2013/3/7

Y1 - 2013/3/7

N2 - An efficient visible light-induced hydrogen evolution system has been developed by using supramolecular porphyrin hexagonal nanocylinders that encapsulate Pt-colloids-deposited TiO2 nanoparticles (Pt/TiO 2) in the internal cavity. First, porphyrin nanocylinders structurally controlled by encapsulated Pt/TiO2 are prepared via a solvent mixture technique. The bar-shaped structure composed of Pt/TiO 2 and zinc meso-tetra(4-pyridyl)porphyrin [ZnP(Py)4] is formed with the aid of a surfactant: cetyltrimethylammonium bromide (CTAB) in a DMF/H2O mixture solution [denoted as Pt/TiO2-ZnP(Py) 4 nanorods]. In scanning electron microscopy (SEM) measurements, ZnP(Py)4 pristine hexagonal nanocylinder with a large hollow structure [denoted as ZnP(Py)4 nanocylinder] was observed, whereas the hollow hole was completely closed in case of Pt/TiO2-ZnP(Py) 4 nanorods. X-ray diffraction (XRD) analyses also revealed that ZnP(Py)4 alignment in the nanorod was based on the stacked-assemblies of ZnP(Py)4 coordinated hexagonal formations. These results clearly indicate that Pt colloids-deposited TiO2 nanoparticles (Pt/TiO 2) were successfully encapsulated within a ZnP(Py)4 hexagonal nanocylinder. Pt/TiO2-ZnP(Py)4 also shows a broadened absorption in the visible region because of aggregation of ZnP(Py)4. Then, Pt/TiO2-ZnP(Py)4 exhibited efficient hydrogen evolution under visible light irradiation, whereas no hydrogen was evolved in the case of Pt/TiO2 without ZnP(Py) 4. In addition, the hydrogen evolution efficiency of Pt/TiO 2-ZnP(Py)4 nanorods per unit weight of Pt was two orders magnitude greater than that of the nonencapsulated system: Pt/TiO2 and ZnP(Py)4 nanocylinder composites [Pt/TiO2 + ZnP(Py)4 composites]. Finally, the photodynamics of the excited state of Pt/TiO2-ZnP(Py)4 nanorods was examined by femtosecond time-resolved transient absorption spectroscopy to clarify the photocatalytic mechanism.

AB - An efficient visible light-induced hydrogen evolution system has been developed by using supramolecular porphyrin hexagonal nanocylinders that encapsulate Pt-colloids-deposited TiO2 nanoparticles (Pt/TiO 2) in the internal cavity. First, porphyrin nanocylinders structurally controlled by encapsulated Pt/TiO2 are prepared via a solvent mixture technique. The bar-shaped structure composed of Pt/TiO 2 and zinc meso-tetra(4-pyridyl)porphyrin [ZnP(Py)4] is formed with the aid of a surfactant: cetyltrimethylammonium bromide (CTAB) in a DMF/H2O mixture solution [denoted as Pt/TiO2-ZnP(Py) 4 nanorods]. In scanning electron microscopy (SEM) measurements, ZnP(Py)4 pristine hexagonal nanocylinder with a large hollow structure [denoted as ZnP(Py)4 nanocylinder] was observed, whereas the hollow hole was completely closed in case of Pt/TiO2-ZnP(Py) 4 nanorods. X-ray diffraction (XRD) analyses also revealed that ZnP(Py)4 alignment in the nanorod was based on the stacked-assemblies of ZnP(Py)4 coordinated hexagonal formations. These results clearly indicate that Pt colloids-deposited TiO2 nanoparticles (Pt/TiO 2) were successfully encapsulated within a ZnP(Py)4 hexagonal nanocylinder. Pt/TiO2-ZnP(Py)4 also shows a broadened absorption in the visible region because of aggregation of ZnP(Py)4. Then, Pt/TiO2-ZnP(Py)4 exhibited efficient hydrogen evolution under visible light irradiation, whereas no hydrogen was evolved in the case of Pt/TiO2 without ZnP(Py) 4. In addition, the hydrogen evolution efficiency of Pt/TiO 2-ZnP(Py)4 nanorods per unit weight of Pt was two orders magnitude greater than that of the nonencapsulated system: Pt/TiO2 and ZnP(Py)4 nanocylinder composites [Pt/TiO2 + ZnP(Py)4 composites]. Finally, the photodynamics of the excited state of Pt/TiO2-ZnP(Py)4 nanorods was examined by femtosecond time-resolved transient absorption spectroscopy to clarify the photocatalytic mechanism.

UR - http://www.scopus.com/inward/record.url?scp=84874857960&partnerID=8YFLogxK

U2 - 10.1021/jp400381h

DO - 10.1021/jp400381h

M3 - Article

AN - SCOPUS:84874857960

SN - 1932-7447

VL - 117

SP - 4441

EP - 4449

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

IS - 9

ER -

Remarkable enhancement of photocatalytic hydrogen evolution efficiency utilizing an internal cavity of supramolecular porphyrin hexagonal nanocylinders under visible-light irradiation

Abstract

Access to Document

Fingerprint

Cite this