Titanium dioxide/carbon nitride nanosheet nanocomposites for gas phase CO2 photoreduction under UV-visible irradiation
File(s)TiO2-CN SI 021018_Accepted.docx (6.01 MB) TiO2-CN 021018_Accepted.docx (18.75 MB)
Supporting information
Accepted version
Author(s)
Type
Journal Article
Abstract
In the field of photocatalysis and particularly that of CO2 photoreduction, the formulation of nanocomposites provids avenues to design a material platform with a unique set of structural, optoelectronic and chemical features thereby addressing shortcomings of single-phase materials and allowing synergistic effects. In this work, inorganic/organic composite photocatalysts for CO2 reduction comprised of titanium dioxide (TiO2) and carbon nitride nanosheets (CNNS) were synthesized using a hydrothermal in-situ growth method. Specifically, pre-formed CNNS were used to synthesize TiO2/CNNS heterostructures with control over the TiO2 facet formation. This synthesis approach improved the catalytic properties by increasing CO2 adsorption capacity and facilitating charge transfer. The materials were characterised by various spectroscopic, imaging, and analytical techniques to investigate their structural (from nano- to macroscale), chemical, and optical properties. TiO2 nanoparticles were efficiently grown on the CNNS. The CO2 adsorption capacity of the composites was measured, and they were tested for CO2 photoreduction under UV-Vis illumination with hydrogen as the reducing agent in a heterogeneous gas-solid system to combine CO2 capture and conversion into a single-step process. Catalytic tests were performed without adding any precious metal co-catalyst. The composites exhibited enhanced CO2 adsorption capacity and photocatalytic CO2 conversion compared to their constituent materials (> ten-fold increase) and outperformed the TiO2 P25 benchmark material. The TiO2/CNNS composite with more {001} TiO2 facets was the most catalytically active. Further investigations using transient absorption spectroscopy (TAS) revealed the control of facet formation improved interfacial transfer at the TiO2/CNNS junction. A photocatalytic mechanism was proposed based on the spectroscopic analyses as well as the CO2 adsorption, and CO2 conversion results.
Date Issued
2019-03-01
Date Acceptance
2018-10-07
Citation
Applied Catalysis B: Environmental, 2019, 242, pp.369-378
ISSN
0926-3373
Publisher
Elsevier
Start Page
369
End Page
378
Journal / Book Title
Applied Catalysis B: Environmental
Volume
242
Copyright Statement
© 2018 Elsevier B.V. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/
Sponsor
Commission of the European Communities
Engineering and Physical Sciences Research Council
Engineering & Physical Science Research Council (EPSRC)
Kaust
The Royal Society
Grant Number
291482
EP/N024206/1
CHEDG_P61719
RSG\R1\180434
Subjects
Science & Technology
Physical Sciences
Technology
Chemistry, Physical
Engineering, Environmental
Engineering, Chemical
Chemistry
Engineering
Carbon nitride nanosheets
TiO2
001 facets
CO2 reduction
Heterojunction
GRAPHITIC CARBON NITRIDE
ENHANCED PHOTOCATALYTIC ACTIVITY
METAL-ORGANIC FRAMEWORKS
ANATASE TIO2
001 FACETS
HYDROGEN EVOLUTION
BAND ALIGNMENT
SEMICONDUCTORS
EFFICIENT
REDUCTION
0306 Physical Chemistry (Incl. Structural)
0904 Chemical Engineering
0907 Environmental Engineering
Physical Chemistry
Publication Status
Published
Date Publish Online
2018-10-09