%T Fabrication of highly efficient and stable indirect Z-scheme assembly of AgBr/TiO 2 via graphene as a solid-state electron mediator for visible light induced enhanced photocatalytic H 2 production
%A N. Shehzad
%A M. Tahir
%A K. Johari
%A T. Murugesan
%A M. Hussain
%I Elsevier B.V.
%V 463
%P 445-455
%K Assembly; Charge transfer; Chemical bonds; Electrons; Energy gap; Fabrication; Fourier transform infrared spectroscopy; Graphene; Hole concentration; Hydrogen; Hydrogen production; Light; Light absorption; Optical properties; Photocatalysts; Redox reactions; Silver halides; Solar energy; Surface reactions; Titanium dioxide, Adsorption and desorptions; Photocatalytic activities; Possible mechanisms; Silver bromide; Solid-state electron; Titania; Two step synthesis method; Visible light induced, Bromine compounds
%X In this study, indirect Z-schematic assembly of AgBr and TiO 2 via graphene as a solid-state electron mediator was developed and investigated for photocatalytic H 2 production. The AgBr/rGO/TiO 2 was fabricated using facile two-step synthesis method which includes the growth of AgBr and deposition of TiO 2 on graphene oxide sheets followed by partial reduction through reflux method. The photocatalysts were characterized using TEM, XRD, XPS, FTIR, nitrogen (N 2 ) adsorption and desorption, Raman, PL and UV�Vis spectroscopy to understand morphology, structure, chemical and optical properties. Alterations in band structures, elevation of conduction band positions and reduction in band gap energies of rGO-modified AgBr/TiO 2 photocatalysts were evaluated. The performance of AgBr/rGO/TiO 2 exhibited 2025 ppm of H 2 production, which was 7 fold higher than AgBr/TiO 2 (289 ppm), 2.3 fold higher than rGO/TiO 2 (885 ppm) and 13.4 fold higher than TiO 2 (151 ppm). Enhanced photocatalytic activity of Z-schematic composites can be attributed to strong interfacial bonding (AgBr�rGO�TiO 2 ), efficient transfer of electrons due to synergistic effect of AgBr and rGO as well as extended light absorption due to highly light sensitive AgBr. In addition, yield of H 2 production was decreased above 5 AgBr loading and dosage of 0.10 g of photocatalyst due to incompatibility of ratio and shielding effect of particles. Moreover, with increase of temperature and concentration of hole scavenger, yield of H 2 production was gradually increased which demonstrated the contribution of H 2 from photoreforming of hole scavenger. Based on the experimental and characterizations results, a possible mechanism that highlighted the surface redox reactions and charge transfer pattern on AgBr/rGO/TiO 2 was developed. Thus, indirect Z-scheme assembly of AgBr/rGO/TiO 2 could be a promising photocatalyst for solar energy assisted H 2 production. © 2018 Elsevier B.V.
%D 2019
%R 10.1016/j.apsusc.2018.08.250
%O cited By 72
%J Applied Surface Science
%L scholars12317