Photocatalytic hydrogen evolution over the isostructural titanates: Ba3Li2Ti8O20 and Na2Ti6O13 modified with metal oxide nanoparticles. (25th January 2018)

• Record Type: Journal Article
• Authors: Garay-Rodríguez, Luis F.; Huerta-Flores, Ali M.; Torres-Martínez, Leticia M.; Moctezuma, Edgar
• Is Part Of: International journal of hydrogen energy. Volume 43:Number 4(2018)
• Page Start: 2148
• Page End: 2159
• Publication Date: 2018-01-25
• Subjects: Tunnel structure -- Titanates -- Hydrogen evolution -- Cocatalysts; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2017.12.004
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Isostructural titanates exhibiting rectangular tunnel structure with the general formula Na2 Ti6 O13 and Ba3 Li2 Ti8 O20, were synthesized by solid state and sol-gel methods. The structural, morphological, optical, textural and electrical properties of the materials were characterized by XRD, SEM, UV-vis, BET and EIS. The photocatalytic activity for hydrogen evolution of the materials was evaluated under UV light. Na2 Ti6 O13 exhibited higher activity (120 μmol/gh) than Ba3 Li2 Ti8 O20 (30 μmol/gh), and it was attributed to the distortion of the octahedrons in Ba3 Li2 Ti8 O20, which increases the recombination of charges in the material. Additionally, the 1D dimension obtained in Na2 Ti6 O13 promotes a better charge separation, transport and utilization in this phase. The activity of the materials was enhanced with the incorporation of metal oxide nanoparticles MO (M = Cu, Ni) as cocatalysts. The activity of Ba3 Li2 Ti8 O20 increased 10 times with the addition of CuO (240 μmol/gh), while the activity of Na2 Ti6 O13 increased 3.5 times (416 μmol/gh). This improvement in the photocatalytic activity of the isostructural titanates was attributed to the formation of a p-n heterostructure between n-type titanates and p-type CuO, which promoted an enhanced charge separation, transference and utilization. Graphical abstract: Highlights: Photocatalytic H2 evolution on Ba and Na tunnel isostructural titanates is studied. Activity of Ba3 Li2 Ti8 O20 (30 μmol/gh) is reported herein for the first time. A correlation of physicochemical properties with catalytic activity is discussed. Deposition of CuO and NiO nanoparticles increased significantly the H2 evolution. The highest activity was obtained by Na2 Ti6 O13 modified with CuO (416 μmol/gh).