2D-montmorillonite-dispersed g-C3N4/TiO2 2D/0Dnanocomposite for enhanced photo-induced H2 evolution from glycerol-water mixture

• Published in: Applied surface science 2019-03, Vol.471, p.1053-1064
• Main Authors: Fajrina, Nur, Tahir, Muhammad
• Format: Article
• Language: English
• Subjects: g-C3N4; Hydrogen production; Montmorillonite; Photo-catalysis; TiO2; Z-scheme
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2018.12.076

[Display omitted] •g-C3N4/MMT/TiO2 composite synthesized and tested for photocatalytic H2 production.•With g-C3N4/MMT/TiO2, H2 of 4425 ppm h−1 g−1 obtained, 2.12 times higher than TiO2.•Glycerol solution with pH 7 gave highest H2 yield, 14 times more than using pure water.•2D MMT-dispersed with 2D/0D g-C3N4/TiO2 promoted H2 yield by trapping electrons.•Stability exhibits prolong g-C3N4/MMT/TiO2 activity for H2 production in cyclic runs. Montmorillonite (MMT) dispersed g-C3N4/TiO2 hybrid nanocomposite for enhanced photo-catalytic hydrogen production from glycerol-water mixture has been investigated. The newly designed composite photo-catalysts were fabricated through a sol-gel assisted hydrothermal method and were characterized by XRD, XPS, SEM, EDX, TEM, FTIR, UV–Vis, Raman and PL spectroscopy. Well-designed g-C3N4/MMT/TiO2 heterojunction composite was obtained with 2D MMT structure, which promoted both visible light absorption and hindered charges recombination rate. The modification of 2D/0D g-C3N4/TiO2 heterojunction with 2D MMT sheets enhances H2 production due to MMT works as a mediator for effective charges trapping and transportation within the composite structure. The g-C3N4/MMT/TiO2 photo-catalyst exhibits highest H2 production of 4425 ppm h−1 g−1 at pH 7.0, which was 2.12 times higher than the pure TiO2 (2085 ppm h−1 g−1). In addition, increasing catalyst loading promotes more H2 evolution and among the different sacrificial reagents, glycerol-water mixture gave highest H2 production due to the presence of α-hydrogen atoms attached to carbon atoms. The enhanced photo-catalytic efficiency can be attributed to synergistic effect of MMT with g-C3N4/TiO2 heterojunction composite, appropriate band structure and transportation of electrons–holes with their hindered recombination rate. These composite catalysts exhibited excellent photo-catalytic stability for H2 production in cyclic runs. Possible reaction mechanism for hydrogen production over g-C3N4/MMT/TiO2 composite has been explained based on the experimental results. The finding of this work would be fruitful for hydrogen production applications with all sustainable systems.