Effects of electron charge density and particle size of alkali metal titanate nanotube-supported Pt photocatalysts on production of H2 from neat alcohol

Chiu Hsun Lin, Jiunn Hsing Chao, Wei Je Tsai, Meng Jou He, Ting Ju Chiang

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Pt nanoparticles (PtNPs) in the range of 1.0-3.0 nm were deposited on alkali titanate nanotubes (MTNTs = M2-xHxTi3O7, M = Li+, Na+, K+ and Cs+) by wet impregnation. While most of the physical properties of Pt/MTNTs remained almost constant, the oxidation state and size of PtNPs varied systematically with the size of the cations of MTNTs. XPS indicated that the binding energy of Pt in Pt/MTNTs was reduced to a lower value than that of Pt0, yielding a Ptδ- oxidation state. Diffuse-reflectance infrared Fourier transform spectroscopy coupling with CO adsorption studies confirmed the formation of the Ptδ- state in Pt/MTNTs. Thus, electrons were transferred from MTNTs to PtNPs establishing an electric double layer at the interface between PtNP and MTNT supports, and the degree of electron transfer increased with the size of the cations in MTNTs. HRTEM revealed that the mean sizes of PtNPs followed the order, Pt/LiTNTs < Pt/NaTNTs < Pt/KTNTs < Pt/CsTNTs. TPR showed that the reducibility of PtOx/MTNTs determined the order of PtNPs size. In the photocatalytic production of H2 (2H+ + 2e-→ H2), since H2 is produced at the interfacial Pt sites, the electron charge density and the particle size of PtNPs are the two competing factors in producing H2. Photoluminescence studies revealed that the initial increase in electron density on PtNPs reduced the recombination of h+-e- pairs and increased H2 yields, but a further increase in charge density enhanced the recombination of h+-e- pairs and lowered the H2 yield. PtNPs in Pt/KTNTs had a moderate charge density and a moderate particle size, and so, produced a maximum amount of H2 among Pt/MTNTs.

Original languageEnglish
Pages (from-to)23743-23753
Number of pages11
JournalPhysical Chemistry Chemical Physics
Volume16
Issue number43
DOIs
Publication statusPublished - 2014 Oct 15

Fingerprint

Alkali Metals
Photocatalysts
Charge density
alkali metals
Nanotubes
nanotubes
alcohols
Particle size
Alcohols
Nanoparticles
nanoparticles
Electrons
electrons
Cations
cations
Oxidation
oxidation
Alkalies
Carbon Monoxide
Binding energy

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this

@article{49e5640c0f80484b9c891b2f780270af,
title = "Effects of electron charge density and particle size of alkali metal titanate nanotube-supported Pt photocatalysts on production of H2 from neat alcohol",
abstract = "Pt nanoparticles (PtNPs) in the range of 1.0-3.0 nm were deposited on alkali titanate nanotubes (MTNTs = M2-xHxTi3O7, M = Li+, Na+, K+ and Cs+) by wet impregnation. While most of the physical properties of Pt/MTNTs remained almost constant, the oxidation state and size of PtNPs varied systematically with the size of the cations of MTNTs. XPS indicated that the binding energy of Pt in Pt/MTNTs was reduced to a lower value than that of Pt0, yielding a Ptδ- oxidation state. Diffuse-reflectance infrared Fourier transform spectroscopy coupling with CO adsorption studies confirmed the formation of the Ptδ- state in Pt/MTNTs. Thus, electrons were transferred from MTNTs to PtNPs establishing an electric double layer at the interface between PtNP and MTNT supports, and the degree of electron transfer increased with the size of the cations in MTNTs. HRTEM revealed that the mean sizes of PtNPs followed the order, Pt/LiTNTs < Pt/NaTNTs < Pt/KTNTs < Pt/CsTNTs. TPR showed that the reducibility of PtOx/MTNTs determined the order of PtNPs size. In the photocatalytic production of H2 (2H+ + 2e-→ H2), since H2 is produced at the interfacial Pt sites, the electron charge density and the particle size of PtNPs are the two competing factors in producing H2. Photoluminescence studies revealed that the initial increase in electron density on PtNPs reduced the recombination of h+-e- pairs and increased H2 yields, but a further increase in charge density enhanced the recombination of h+-e- pairs and lowered the H2 yield. PtNPs in Pt/KTNTs had a moderate charge density and a moderate particle size, and so, produced a maximum amount of H2 among Pt/MTNTs.",
author = "Lin, {Chiu Hsun} and Chao, {Jiunn Hsing} and Tsai, {Wei Je} and He, {Meng Jou} and Chiang, {Ting Ju}",
year = "2014",
month = "10",
day = "15",
doi = "10.1039/c4cp03503h",
language = "English",
volume = "16",
pages = "23743--23753",
journal = "Physical Chemistry Chemical Physics",
issn = "1463-9076",
publisher = "Royal Society of Chemistry",
number = "43",

}

Effects of electron charge density and particle size of alkali metal titanate nanotube-supported Pt photocatalysts on production of H2 from neat alcohol. / Lin, Chiu Hsun; Chao, Jiunn Hsing; Tsai, Wei Je; He, Meng Jou; Chiang, Ting Ju.

In: Physical Chemistry Chemical Physics, Vol. 16, No. 43, 15.10.2014, p. 23743-23753.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Effects of electron charge density and particle size of alkali metal titanate nanotube-supported Pt photocatalysts on production of H2 from neat alcohol

AU - Lin, Chiu Hsun

AU - Chao, Jiunn Hsing

AU - Tsai, Wei Je

AU - He, Meng Jou

AU - Chiang, Ting Ju

PY - 2014/10/15

Y1 - 2014/10/15

N2 - Pt nanoparticles (PtNPs) in the range of 1.0-3.0 nm were deposited on alkali titanate nanotubes (MTNTs = M2-xHxTi3O7, M = Li+, Na+, K+ and Cs+) by wet impregnation. While most of the physical properties of Pt/MTNTs remained almost constant, the oxidation state and size of PtNPs varied systematically with the size of the cations of MTNTs. XPS indicated that the binding energy of Pt in Pt/MTNTs was reduced to a lower value than that of Pt0, yielding a Ptδ- oxidation state. Diffuse-reflectance infrared Fourier transform spectroscopy coupling with CO adsorption studies confirmed the formation of the Ptδ- state in Pt/MTNTs. Thus, electrons were transferred from MTNTs to PtNPs establishing an electric double layer at the interface between PtNP and MTNT supports, and the degree of electron transfer increased with the size of the cations in MTNTs. HRTEM revealed that the mean sizes of PtNPs followed the order, Pt/LiTNTs < Pt/NaTNTs < Pt/KTNTs < Pt/CsTNTs. TPR showed that the reducibility of PtOx/MTNTs determined the order of PtNPs size. In the photocatalytic production of H2 (2H+ + 2e-→ H2), since H2 is produced at the interfacial Pt sites, the electron charge density and the particle size of PtNPs are the two competing factors in producing H2. Photoluminescence studies revealed that the initial increase in electron density on PtNPs reduced the recombination of h+-e- pairs and increased H2 yields, but a further increase in charge density enhanced the recombination of h+-e- pairs and lowered the H2 yield. PtNPs in Pt/KTNTs had a moderate charge density and a moderate particle size, and so, produced a maximum amount of H2 among Pt/MTNTs.

AB - Pt nanoparticles (PtNPs) in the range of 1.0-3.0 nm were deposited on alkali titanate nanotubes (MTNTs = M2-xHxTi3O7, M = Li+, Na+, K+ and Cs+) by wet impregnation. While most of the physical properties of Pt/MTNTs remained almost constant, the oxidation state and size of PtNPs varied systematically with the size of the cations of MTNTs. XPS indicated that the binding energy of Pt in Pt/MTNTs was reduced to a lower value than that of Pt0, yielding a Ptδ- oxidation state. Diffuse-reflectance infrared Fourier transform spectroscopy coupling with CO adsorption studies confirmed the formation of the Ptδ- state in Pt/MTNTs. Thus, electrons were transferred from MTNTs to PtNPs establishing an electric double layer at the interface between PtNP and MTNT supports, and the degree of electron transfer increased with the size of the cations in MTNTs. HRTEM revealed that the mean sizes of PtNPs followed the order, Pt/LiTNTs < Pt/NaTNTs < Pt/KTNTs < Pt/CsTNTs. TPR showed that the reducibility of PtOx/MTNTs determined the order of PtNPs size. In the photocatalytic production of H2 (2H+ + 2e-→ H2), since H2 is produced at the interfacial Pt sites, the electron charge density and the particle size of PtNPs are the two competing factors in producing H2. Photoluminescence studies revealed that the initial increase in electron density on PtNPs reduced the recombination of h+-e- pairs and increased H2 yields, but a further increase in charge density enhanced the recombination of h+-e- pairs and lowered the H2 yield. PtNPs in Pt/KTNTs had a moderate charge density and a moderate particle size, and so, produced a maximum amount of H2 among Pt/MTNTs.

UR - http://www.scopus.com/inward/record.url?scp=84907979030&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84907979030&partnerID=8YFLogxK

U2 - 10.1039/c4cp03503h

DO - 10.1039/c4cp03503h

M3 - Article

AN - SCOPUS:84907979030

VL - 16

SP - 23743

EP - 23753

JO - Physical Chemistry Chemical Physics

JF - Physical Chemistry Chemical Physics

SN - 1463-9076

IS - 43

ER -