Tuning Photocatalytic Performance of Multilayer ZnO for Water Splitting by Biaxial Strain Composites

Abstract

Novel two-dimensional (2D) materials have received extensive attention in the field of photocatalysis due to their unique properties. Traditional ZnO material with wurtzite structure transforms into a stable graphite-like structure that has the characteristics of 2D material when its thickness is less than a few atomic layers. In this work, using first-principles calculations, we investigated the potential of multilayer graphite-like ZnO as a photocatalyst for water splitting. The results showed that multilayer ZnO is a series of direct bandgap semiconductors, and their band edge positions all straddle the redox potential of water. Increasing with the number of layers, the bandgap of multilayer ZnO decreased from 3.20 eV for one layer to 2.21 eV for six layers, and visible light absorption capacity was significantly enhanced. Hence, multilayer ZnO was indeed promising for photocatalytic water splitting. Furthermore, suitable biaxial tensile strain could decrease the bandgap and maintain the stable graphite-like structure at a broader thickness range. In contrast, excessive biaxial tensile strain could change the redox capacity of multilayer ZnO and prevent it from catalyzing water splitting. Our theoretical results show that six-layer ZnO under 1% biaxial strain had direct bandgap of 2.07 eV and represents the most excellent photocatalytic performance among these multilayer ZnO materials.

First principles study on thickness dependent structural and electronic properties unveiling the growth and stability of 2D layered II–VI semiconducting compounds

“…The MO layer possesses a similar bond length in both odd and even layered cases and these results are quite consistent with earlier works. 6,7,45 The critical thickness for stabilizing the WZ slab as well as the 2D-MO slab is also estimated by comparing the energetics of both cases, as shown in Fig. 3.…”

Tandem Structures Semiconductors Based on TiO2_SnO2 and ZnO_SnO2 for Photocatalytic Organic Pollutant Removal

“…Merging the sustainability with durability may be the key of transferring the photocatalytic process from the laboratory scale up to large applications. Until now there are many wide gap oxides (TiO 2 [ 4 , 5 ], SnO 2 [ 6 , 7 ], and ZnO [ 8 , 9 ]) and narrow band gap materials (Bi 2 WO 6 [ 10 , 11 ], Ag 3 PO 4 [ 12 , 13 ], BiPO 4 [ 14 , 15 ], g-C 3 N 4 [ 16 , 17 ], WO 3 [ 18 , 19 ], and BiOX [ 20 , 21 ]) studied for the potocatalytic removal of wastewater organic contaminants and indoor pollutants. The mono-components photocatalyst have disadvantages such as narrow visible light absorption [ 22 , 23 ], low specific surface area [ 24 , 25 ], and fast charge carriers recombination [ 26 , 27 ].…”

Electrospinning Preparation of GaN:ZnO Solid Solution Nanorods with Visible-Light-Driven Photocatalytic Activity toward H2 Production

“…Particularly, the use of photocatalytic water splitting for hydrogen production is an attractive strategy in the field of energy conversion with abundant solar energy, since the pioneering report of photoelectrochemical water splitting was published in 1972 [2]. Currently, a lot of photocatalysts, such as TiO 2 [3][4][5], WO 3 [6,7], g-C 3 N 4 [8][9][10], ZnO [11][12][13], and metal complexes [14][15][16], have been employed for the photocatalytic water splitting reaction. However, it has been demonstrated that most of these photocatalysts with wide band gaps are only active under UV irradiation.…”