Metals free MWCNTs@TiO                         2                         @MMT heterojunction composite with MMT as a mediator for fast charges separation towards visible light driven photocatalytic hydrogen evolution

Muhammad Umer; Muhammad Tahir; Muhammad Usman Azam; Mohammad Musaab Jaffar

doi:10.1016/j.apsusc.2018.08.240

Metals free MWCNTs@TiO ₂ @MMT heterojunction composite with MMT as a mediator for fast charges separation towards visible light driven photocatalytic hydrogen evolution

Muhammad Umer
, Muhammad Tahir
, Muhammad Usman Azam
, Mohammad Musaab Jaffar

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

82 Citations (Scopus)

Abstract

Constructing heterojunctions with low-cost materials functional under solar energy is an important way for efficient hydrogen production for energy management applications. In this study, multiwall carbon nanotubes (MWCNTs) modified TiO ₂ 1D/0D heterojunction dispersed in 2D montmorillonite (MMT) nanoclay was designed and fabricated using a facile sol-gel and wet impregnation approach. The samples were characterized by XRD, Raman, FESEM, HRTEM, FTIR, UV–vis and PL-spectroscopy techniques. Dispersing 1D/0D MWCNTs/TiO ₂ on the 2D MMT structure extends visible light absorption, shorten charges migration distance and provides abundant active sites. The performance of samples was investigated for dynamic photocatalytic H ₂ evolution with different sacrificial reagents under visible light irradiations. The MWCNTs/TiO ₂ /MMT heterojunction composite exhibits the highest H ₂ evolution rate of 1888 ppm h ⁻¹ , which is about 1.49, 3.07 and 7.12 folds higher than MWCNTs/TiO ₂ , MMT/TiO ₂ and pure TiO ₂ samples, respectively. Among the different sacrificial reagents, highest H ₂ production was obtained using glycerol-water mixture due to the presence of α-hydrogen atoms attached to carbon atoms. Next, the photocatalytic turn-over productivity (PTOP) was estimated which demonstrated the molecular H ₂ production rate with the photon-energy utilization. The maximum PTOP for H ₂ production was achieved over MWCNTs/TiO ₂ /MMT heterojunction composite, 5.94 times higher than using bare TiO ₂ NPs. The improved charges efficiency due to the synergistic effect between MWCNTs/TiO ₂ /MMT in 1D/OD/2D heterojunctions is critical for enhanced and dynamic H ₂ evolution. The ternary composite exhibited excellent and stable performance for H ₂ production. This study suggests that constructing heterojunction of low cost coupling materials with TiO ₂ can provide an efficient way for H ₂ production under solar energy.

Original language	English
Pages (from-to)	747-757
Number of pages	11
Journal	Applied Surface Science
Volume	463
DOIs	https://doi.org/10.1016/j.apsusc.2018.08.240
Publication status	Published - Jan 1 2019
Externally published	Yes

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 7 Affordable and Clean Energy

Keywords

Heterojunction
Montmorillonite nanoclay
MWCNTs/TiO
Photocatalytic H evolution
Photocatalytic turnover productivity

ASJC Scopus subject areas

General Chemistry
Condensed Matter Physics
General Physics and Astronomy
Surfaces and Interfaces
Surfaces, Coatings and Films

Access to Document

10.1016/j.apsusc.2018.08.240

Cite this

Umer, M., Tahir, M., Azam, M. U., & Jaffar, M. M. (2019). Metals free MWCNTs@TiO ₂ @MMT heterojunction composite with MMT as a mediator for fast charges separation towards visible light driven photocatalytic hydrogen evolution Applied Surface Science, 463, 747-757. https://doi.org/10.1016/j.apsusc.2018.08.240

Metals free MWCNTs@TiO ₂ @MMT heterojunction composite with MMT as a mediator for fast charges separation towards visible light driven photocatalytic hydrogen evolution . / Umer, Muhammad; Tahir, Muhammad; Azam, Muhammad Usman et al.
In: Applied Surface Science, Vol. 463, 01.01.2019, p. 747-757.

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

Umer, M, Tahir, M, Azam, MU & Jaffar, MM 2019, ' Metals free MWCNTs@TiO ₂ @MMT heterojunction composite with MMT as a mediator for fast charges separation towards visible light driven photocatalytic hydrogen evolution ', Applied Surface Science, vol. 463, pp. 747-757. https://doi.org/10.1016/j.apsusc.2018.08.240

Umer M, Tahir M, Azam MU, Jaffar MM. Metals free MWCNTs@TiO ₂ @MMT heterojunction composite with MMT as a mediator for fast charges separation towards visible light driven photocatalytic hydrogen evolution Applied Surface Science. 2019 Jan 1;463:747-757. doi: 10.1016/j.apsusc.2018.08.240

Umer, Muhammad ; Tahir, Muhammad ; Azam, Muhammad Usman et al. / Metals free MWCNTs@TiO ₂ @MMT heterojunction composite with MMT as a mediator for fast charges separation towards visible light driven photocatalytic hydrogen evolution In: Applied Surface Science. 2019 ; Vol. 463. pp. 747-757.

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abstract = " Constructing heterojunctions with low-cost materials functional under solar energy is an important way for efficient hydrogen production for energy management applications. In this study, multiwall carbon nanotubes (MWCNTs) modified TiO 2 1D/0D heterojunction dispersed in 2D montmorillonite (MMT) nanoclay was designed and fabricated using a facile sol-gel and wet impregnation approach. The samples were characterized by XRD, Raman, FESEM, HRTEM, FTIR, UV–vis and PL-spectroscopy techniques. Dispersing 1D/0D MWCNTs/TiO 2 on the 2D MMT structure extends visible light absorption, shorten charges migration distance and provides abundant active sites. The performance of samples was investigated for dynamic photocatalytic H 2 evolution with different sacrificial reagents under visible light irradiations. The MWCNTs/TiO 2 /MMT heterojunction composite exhibits the highest H 2 evolution rate of 1888 ppm h −1 , which is about 1.49, 3.07 and 7.12 folds higher than MWCNTs/TiO 2 , MMT/TiO 2 and pure TiO 2 samples, respectively. Among the different sacrificial reagents, highest H 2 production was obtained using glycerol-water mixture due to the presence of α-hydrogen atoms attached to carbon atoms. Next, the photocatalytic turn-over productivity (PTOP) was estimated which demonstrated the molecular H 2 production rate with the photon-energy utilization. The maximum PTOP for H 2 production was achieved over MWCNTs/TiO 2 /MMT heterojunction composite, 5.94 times higher than using bare TiO 2 NPs. The improved charges efficiency due to the synergistic effect between MWCNTs/TiO 2 /MMT in 1D/OD/2D heterojunctions is critical for enhanced and dynamic H 2 evolution. The ternary composite exhibited excellent and stable performance for H 2 production. This study suggests that constructing heterojunction of low cost coupling materials with TiO 2 can provide an efficient way for H 2 production under solar energy.",

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