Impact of the annealing temperature on Pt/g-C3N4 structure, activity and selectivity between photodegradation and water splitting

Marine Caux*, Federica Fina, John T. S. Irvine, Hicham Idriss, Russell Howe

*Corresponding author for this work

Research output: Contribution to journalArticle

23 Citations (Scopus)
6 Downloads (Pure)

Abstract

This work presents a systematic study of the effect of fabrication temperature (450 to 650 °C) on the structure and electronic properties of g-C3N4 prepared from melamine. The work is conducted by X-ray diffraction, elemental analysis, BET nitrogen adsorption, UV–vis absorption, and electron paramagnetic resonance (EPR). The photocatalytic activity is tested for hydrogen production in the presence of oxalic acid (OA) as well as triethanolamine (TEOA). A considerable change in the morphology is observed with increasing the synthesis temperature resulting in an increase of the surface area, likely due to thermal etching. The decrease of charge carriers’ concentration, per unit surface area, with increasing annealing temperature may be due to the decrease of the conjugation of the polymer. Probing the activity of in situ reduced Pt/g-C3N4 for hydrogen evolution reinforced this conclusion, the rate of hydrogen evolution per unit area for OA as well as TEOA decreased with increasing annealing temperature. An interesting finding is the correlation between CO2:H2 ratio and the increase in the band gap of g-C3N4 prepared at different temperatures when using oxalic acid as an electron donor. This suggests that water oxidation becomes easier with increasing band gap energy, probably due to a lowering of the valence band edge.

Original languageEnglish
Pages (from-to)182-188
Number of pages7
JournalCatalysis Today
Volume287
Early online date20 Nov 2016
DOIs
Publication statusPublished - 1 Jun 2017

Fingerprint

Photodegradation
Oxalic Acid
Oxalic acid
Annealing
Water
Triethanolamine
Hydrogen
Energy gap
Temperature
Melamine
Hydrogen production
Valence bands
Charge carriers
Electronic properties
Carrier concentration
Paramagnetic resonance
Etching
Polymers
Nitrogen
Adsorption

Keywords

  • Electron paramagnetic resonance
  • G-CN
  • Hydrogen production
  • Photocatalysis
  • Synthesis temperature

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)

Cite this

Impact of the annealing temperature on Pt/g-C3N4 structure, activity and selectivity between photodegradation and water splitting. / Caux, Marine; Fina, Federica; Irvine, John T. S.; Idriss, Hicham; Howe, Russell.

In: Catalysis Today, Vol. 287, 01.06.2017, p. 182-188.

Research output: Contribution to journalArticle

Caux, Marine ; Fina, Federica ; Irvine, John T. S. ; Idriss, Hicham ; Howe, Russell. / Impact of the annealing temperature on Pt/g-C3N4 structure, activity and selectivity between photodegradation and water splitting. In: Catalysis Today. 2017 ; Vol. 287. pp. 182-188.
@article{7497ab63f4644c358a1db4ba03c8e0fa,
title = "Impact of the annealing temperature on Pt/g-C3N4 structure, activity and selectivity between photodegradation and water splitting",
abstract = "This work presents a systematic study of the effect of fabrication temperature (450 to 650 °C) on the structure and electronic properties of g-C3N4 prepared from melamine. The work is conducted by X-ray diffraction, elemental analysis, BET nitrogen adsorption, UV–vis absorption, and electron paramagnetic resonance (EPR). The photocatalytic activity is tested for hydrogen production in the presence of oxalic acid (OA) as well as triethanolamine (TEOA). A considerable change in the morphology is observed with increasing the synthesis temperature resulting in an increase of the surface area, likely due to thermal etching. The decrease of charge carriers’ concentration, per unit surface area, with increasing annealing temperature may be due to the decrease of the conjugation of the polymer. Probing the activity of in situ reduced Pt/g-C3N4 for hydrogen evolution reinforced this conclusion, the rate of hydrogen evolution per unit area for OA as well as TEOA decreased with increasing annealing temperature. An interesting finding is the correlation between CO2:H2 ratio and the increase in the band gap of g-C3N4 prepared at different temperatures when using oxalic acid as an electron donor. This suggests that water oxidation becomes easier with increasing band gap energy, probably due to a lowering of the valence band edge.",
keywords = "Electron paramagnetic resonance, G-CN, Hydrogen production, Photocatalysis, Synthesis temperature",
author = "Marine Caux and Federica Fina and Irvine, {John T. S.} and Hicham Idriss and Russell Howe",
note = "Acknowledgements: The authors would like to thank SABIC as well as EPSRC platform grant [EP/K015540/1] for financial support and the Royal Society of Chemistry for a Wolfson Merit Award. In order to protect intellectual property the data underpinning this publication are not made publicly available. All enquiries about the data should be addressed to mc253@st-andrews.ac.uk.",
year = "2017",
month = "6",
day = "1",
doi = "10.1016/j.cattod.2016.11.007",
language = "English",
volume = "287",
pages = "182--188",
journal = "Catalysis Today",
issn = "0920-5861",
publisher = "Elsevier",

}

TY - JOUR

T1 - Impact of the annealing temperature on Pt/g-C3N4 structure, activity and selectivity between photodegradation and water splitting

AU - Caux, Marine

AU - Fina, Federica

AU - Irvine, John T. S.

AU - Idriss, Hicham

AU - Howe, Russell

N1 - Acknowledgements: The authors would like to thank SABIC as well as EPSRC platform grant [EP/K015540/1] for financial support and the Royal Society of Chemistry for a Wolfson Merit Award. In order to protect intellectual property the data underpinning this publication are not made publicly available. All enquiries about the data should be addressed to mc253@st-andrews.ac.uk.

PY - 2017/6/1

Y1 - 2017/6/1

N2 - This work presents a systematic study of the effect of fabrication temperature (450 to 650 °C) on the structure and electronic properties of g-C3N4 prepared from melamine. The work is conducted by X-ray diffraction, elemental analysis, BET nitrogen adsorption, UV–vis absorption, and electron paramagnetic resonance (EPR). The photocatalytic activity is tested for hydrogen production in the presence of oxalic acid (OA) as well as triethanolamine (TEOA). A considerable change in the morphology is observed with increasing the synthesis temperature resulting in an increase of the surface area, likely due to thermal etching. The decrease of charge carriers’ concentration, per unit surface area, with increasing annealing temperature may be due to the decrease of the conjugation of the polymer. Probing the activity of in situ reduced Pt/g-C3N4 for hydrogen evolution reinforced this conclusion, the rate of hydrogen evolution per unit area for OA as well as TEOA decreased with increasing annealing temperature. An interesting finding is the correlation between CO2:H2 ratio and the increase in the band gap of g-C3N4 prepared at different temperatures when using oxalic acid as an electron donor. This suggests that water oxidation becomes easier with increasing band gap energy, probably due to a lowering of the valence band edge.

AB - This work presents a systematic study of the effect of fabrication temperature (450 to 650 °C) on the structure and electronic properties of g-C3N4 prepared from melamine. The work is conducted by X-ray diffraction, elemental analysis, BET nitrogen adsorption, UV–vis absorption, and electron paramagnetic resonance (EPR). The photocatalytic activity is tested for hydrogen production in the presence of oxalic acid (OA) as well as triethanolamine (TEOA). A considerable change in the morphology is observed with increasing the synthesis temperature resulting in an increase of the surface area, likely due to thermal etching. The decrease of charge carriers’ concentration, per unit surface area, with increasing annealing temperature may be due to the decrease of the conjugation of the polymer. Probing the activity of in situ reduced Pt/g-C3N4 for hydrogen evolution reinforced this conclusion, the rate of hydrogen evolution per unit area for OA as well as TEOA decreased with increasing annealing temperature. An interesting finding is the correlation between CO2:H2 ratio and the increase in the band gap of g-C3N4 prepared at different temperatures when using oxalic acid as an electron donor. This suggests that water oxidation becomes easier with increasing band gap energy, probably due to a lowering of the valence band edge.

KW - Electron paramagnetic resonance

KW - G-CN

KW - Hydrogen production

KW - Photocatalysis

KW - Synthesis temperature

UR - http://www.scopus.com/inward/record.url?scp=85006952343&partnerID=8YFLogxK

U2 - 10.1016/j.cattod.2016.11.007

DO - 10.1016/j.cattod.2016.11.007

M3 - Article

AN - SCOPUS:85006952343

VL - 287

SP - 182

EP - 188

JO - Catalysis Today

JF - Catalysis Today

SN - 0920-5861

ER -