1. Université Paris-Saclay, UMR 8000, CNRS, Institut de Chimie Physique, Orsay 91405, France 2. Materials Research and Technology Department (MRT), Luxembourg Institute of Science and Technology (LIST), Käerjeng 4940, Luxembourg
In this study, the electronic and photocatalytic properties of core-shell heterojunctions photocatalysts with reversible configuration of TiO2 and Bi2O3 layers were studied. The core-shell nanostructure, obtained by efficient control of the sol-gel polymerization and impregnation method of variable precursors of semiconductors, makes it possible to study selectively the role of the interfacial charge transfer in each configuration. The morphological, optical, and chemical composition of the core-shell nanostructures were characterized by high-resolution transmission electron microscopy, UV-visible spectroscopy and X-ray photoelectron spectroscopy. The results show the formation of homogenous TiO2 anatase and Bi2O3 layers with a thickness of around 10 and 8 nm, respectively. The interfacial charge carrier dynamic was tracked using time resolved microwave conductivity and transition photocurrent density. The charge transfer, their density, and lifetime were found to rely on the layout layers in the core-shell nanostructure. In optimal core-shell design, Bi2O3 collects holes from TiO2, leaving electrons free to react and increase by 5 times the photocatalytic efficiency toward H2 generation. This study provides new insight into the importance of the design and elaboration of optimal heterojunction based on the photocatalyst system to improve the photocatalytic activity.
V Kumaravel, S Mathew, J Bartlett, et al.. Photocatalytic hydrogen production using metal doped TiO2: a review of recent advances. Applied Catalysis B: Environmental, 2019, 244: 1021–1064 https://doi.org/10.1016/j.apcatb.2018.11.080
2
M Reza Gholipour, C T Dinh, F Béland, et al.. Nanocomposite heterojunctions as sunlight-driven photocatalysts for hydrogen production from water splitting. Nanoscale, 2015, 7(18): 8187–8208 https://doi.org/10.1039/C4NR07224C
3
N M Ghazzal, N Chaoui, E Aubry, et al.. A simple procedure to quantitatively assess the photoactivity of titanium dioxide films. Journal of Photochemistry and Photobiology A Chemistry, 2010, 215(1): 11–16 https://doi.org/10.1016/j.jphotochem.2010.07.014
4
G D Gesesse, C Wang, B K Chang, et al.. A soft-chemistry assisted strong metal–support interaction on a designed plasmonic core–shell photocatalyst for enhanced photocatalytic hydrogen production. Nanoscale, 2020, 12(13): 7011–7023 https://doi.org/10.1039/C9NR09891G
5
G D Gesesse, T Le Neel, Z Cui, et al.. Plasmonic core-shell nanostructure as an optical photoactive nanolens for enhanced light harvesting and hydrogen production. Nanoscale, 2018, 10(43): 20140–20146 https://doi.org/10.1039/C8NR07475E
6
M Liu, R Inde, M Nishikawa, et al.. Enhanced photoactivity with nanocluster-grafted titanium dioxide photocatalysts. ACS Nano, 2014, 8(7): 7229–7238 https://doi.org/10.1021/nn502247x
7
G Liu, K Du, S Haussener, et al.. Charge transport in two-photon semiconducting structures for solar fuels. ChemSusChem, 2016, 9(20): 2878–2904 https://doi.org/10.1002/cssc.201600773
8
A Naldoni, M Altomare, G Zoppellaro, et al.. Photocatalysis with reduced TiO2: from black TiO2 to cocatalyst-free hydrogen production. ACS Catalysis, 2019, 9(1): 345–364 https://doi.org/10.1021/acscatal.8b04068
9
S J A Moniz, S A Shevlin, D J Martin, et al.. Visible-light driven heterojunction photocatalysts for water splitting – a critical review. Energy & Environmental Science, 2015, 8(3): 731–759 https://doi.org/10.1039/C4EE03271C
10
S Yi, X Zhang, B Wulan, et al.. Non-noble metals applied to solar water splitting. Energy & Environmental Science, 2018, 11(11): 3128–3156 https://doi.org/10.1039/C8EE02096E
11
C Wang, J Li, E Paineau, A Laachachi, et al.. A sol-gel biotemplating route with cellulose nanocrystals to design a photocatalyst for improving hydrogen generation. Journal of Materials Chemistry A, 2020, 8(21): 10779–10786 https://doi.org/10.1039/C9TA12665A
12
L Wei, C Yu, Q Zhang, et al.. TiO2-based heterojunction photocatalysts for photocatalytic reduction of CO2 into solar fuels. Journal of Materials Chemistry A, Materials for Energy and Sustainability, 2018, 6(45): 22411–22436 https://doi.org/10.1039/C8TA08879A
13
J Li, P Jiménez-Calvo, E Paineau, et al.. Metal chalcogenides based heterojunctions and novel nanostructures for photocatalytic hydrogen evolution. Catalysts, 2020, 10(1): 89 https://doi.org/10.3390/catal10010089
14
Y Bessekhouad, N Chaoui, M Trzpit, et al.. UV-vis versus visible degradation of Acid Orange II in a coupled CdS/TiO2 semiconductors suspension. Journal of Photochemistry and Photobiology A Chemistry, 2006, 183(1–2): 218–224 https://doi.org/10.1016/j.jphotochem.2006.03.025
15
D Xu, Y Hai, X Zhang, et al.. Bi2O3 cocatalyst improving photocatalytic hydrogen evolution performance of TiO2. Applied Surface Science, 2017, 400: 530–536 https://doi.org/10.1016/j.apsusc.2016.12.171
16
O F Lopes, K T G Carvalho, W Avansi Jr, et al.. Growth of BiVO4 nanoparticles on a Bi2O3 surface: effect of heterojunction formation on visible irradiation-driven catalytic performance. Journal of Physical Chemistry C, 2017, 121(25): 13747–13756 https://doi.org/10.1021/acs.jpcc.7b03340
17
Y Wu, G Lu, S Li. The doping effect of Bi on TiO2 for photocatalytic hydrogen generation and photodecolorization of rhodamine B. Journal of Physical Chemistry C, 2009, 113(22): 9950–9955 https://doi.org/10.1021/jp9009433
18
L Zhang, X Ye, M Boloor, et al.. Significantly enhanced photocurrent for water oxidation in monolithic Mo: BiVO4/SnO2/Si by thermally increasing the minority carrier diffusion length. Energy & Environmental Science, 2016, 9(6): 2044–2052 https://doi.org/10.1039/C6EE00036C
19
M Xie, X Fu, L Jing, et al.. Long-lived, visible-light-excited charge carriers of TiO2/BiVO4 nanocomposites and their unexpected photoactivity for water splitting. Advanced Energy Materials, 2014, 4(5): 1300995 https://doi.org/10.1002/aenm.201300995
20
C H Ho, C H Chan, Y Huang, et al.. The study of optical band edge property of bismuth oxide nanowires α-Bi2O3. Optics Express, 2013, 21(10): 11965–11972 https://doi.org/10.1364/OE.21.011965
21
Y Bessekhouad, D Robert, J V Weber. Photocatalytic activity of Cu2O/TiO2, Bi2O3/TiO2 and ZnMn2O4/TiO2 heterojunctions. Catalysis Today, 2005, 101(3–4): 315–321 https://doi.org/10.1016/j.cattod.2005.03.038
22
P Y Ayekoe, D Robert, D L Goné. Preparation of effective TiO2/Bi2O3 photocatalysts for water treatment. Environmental Chemistry Letters, 2016, 14(3): 387–393 https://doi.org/10.1007/s10311-016-0565-3
23
N L Reddy, S Emin, M Valant, et al.. Nanostructured Bi2O3@TiO2 photocatalyst for enhanced hydrogen production. International Journal of Hydrogen Energy, 2017, 42(10): 6627–6636 https://doi.org/10.1016/j.ijhydene.2016.12.154
24
S Meng, W Sun, S Zhang, et al.. Insight into the transfer mechanism of photogenerated carriers for WO3/TiO2 heterojunction photocatalysts: Is it the transfer of band-band or Z-scheme? Why? Journal of Physical Chemistry C, 2018, 122(46): 26326–26336 https://doi.org/10.1021/acs.jpcc.8b07524
25
G D Gesesse, C Li, E Paineau, et al.. Enhanced photogenerated charge carriers and photocatalytic activity of biotemplated mesoporous TiO2 films with a chiral nematic structure. Chemistry of Materials, 2019, 31(13): 4851–4863 https://doi.org/10.1021/acs.chemmater.9b01465
26
M Chen, Y Li, Z Wang, et al.. Controllable synthesis of core-shell Bi@amorphous Bi2O3 nanospheres with tunable optical and photocatalytic activity for NO removal. Industrial & Engineering Chemistry Research, 2017, 56(37): 10251–10258 https://doi.org/10.1021/acs.iecr.7b02497
27
M N Ghazzal, H Kebaili, M Joseph, et al.. Photocatalytic degradation of Rhodamine 6G on mesoporous titania films: combined effect of texture and dye aggregation forms. Applied Catalysis B: Environmental, 2012, 115–116: 276–284 https://doi.org/10.1016/j.apcatb.2011.12.016
28
M N Ghazzal, R Wojcieszak, G Raj, et al.. Study of mesoporous CdS-quantum-dot-sensitized TiO2 films by using X-ray photoelectron spectroscopy and AFM. Beilstein Journal of Nanotechnology, 2014, 5: 68–76 https://doi.org/10.3762/bjnano.5.6
29
S Sanna, V Esposito, J W Andreasen, et al.. Enhancement of the chemical stability in confined δ-Bi2O3. Nature Materials, 2015, 14(5): 500–504 https://doi.org/10.1038/nmat4266
30
H Y Jiang, K Cheng, J Lin. Crystalline metallic Au nanoparticle-loaded α-Bi2O3 microrods for improved photocatalysis. Physical Chemistry Chemical Physics, 2012, 14(35): 12114–12121 https://doi.org/10.1039/c2cp42165h
31
M N Ghazzal, N Chaoui, M Genet, et al.. Effect of compressive stress inducing a band gap narrowing on the photoinduced activities of sol–gel TiO2 films. Thin Solid Films, 2011, 520(3): 1147–1154 https://doi.org/10.1016/j.tsf.2011.08.097
32
H J Nam, T Amemiya, M Murabayashi, et al.. Photocatalytic activity of sol-gel TiO2 thin films on various kinds of glass substrates: the effects of Na+ and primary particle size. Journal of Physical Chemistry B, 2004, 108(24): 8254–8259 https://doi.org/10.1021/jp037170t
33
Y Xu, M A A Schoonen. The absolute energy positions of conduction and valence bands of selected semiconducting minerals. American Mineralogist, 2000, 85(3–4): 543–556 https://doi.org/10.2138/am-2000-0416
34
T J Savenije, A J Ferguson, N Kopidakis, et al.. Revealing the dynamics of charge carriers in polymer: fullerene blends using photoinduced time-resolved microwave conductivity. Journal of Physical Chemistry C, 2013, 117(46): 24085–24103 https://doi.org/10.1021/jp406706u
