Bandgap Engineering of the g-ZnO Nanosheet via Cationic–Anionic Passivated Codoping for Visible-Light-Driven Photocatalysis

Abstract

The graphene-like ZnO (g-ZnO) nanosheets were synthesized and shown to exhibit highly photocatalytic activity for the degradation of RhB under ultraviolet irradiation. In this work, we utilize cationic–anionic passivated codoping to explore the potential of the g-ZnO nanosheet for the design of efficient water redox photocatalysts by employing density functional theory calculations with the hybrid HSE06 functional. Our calculations show that anion–cation passivated codoped systems not only are more favorable than the corresponding monodoping in the g-ZnO nanosheet due to the Coulomb interactions but also effectively reduce the band gap without introducing unoccupied states which accelerate the electron–hole recombination. The charge-compensated P–Sc and C–Zr codoped g-ZnO nanosheets are energetically favorable for hydrogen evolution but not insufficient to produce oxygen, indicating that they could serve as Z-scheme photocatalysts. The C–Ti, N–Y, and P–Y codoped systems may be potential potocatalysts for photoelectrochemical water splitting to generate hydrogen due to their appropriate band gaps and band edge positions. In particular, the charge-compensated P–Y codoped g-ZnO nanosheet has the most excellent stability and the largest absorption region of visible light among these codoped systems. Further, we show that P–Y passivated codoping can reduce the overpotentials for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) of the g-ZnO nanosheet, indicating that the OER or HER on the P–Y codoped g-ZnO nanosheet can be easier driven by the irradiation-generated holes or electrons.

Rotation Tunable Photocatalytic Properties of ZnO/GaN Heterostructures

“…Especially, Kang et al show the excellent photocatalytic degradation ability for RhB. Actually, the photocatalytic performance of ZnO nanosheets for water splitting is not good because of the wide bandgap of around 3.3 eV, significantly resulting in a poor solar energy utilization. Combining two different semiconductors to construct a heterostructure is an effective strategy for enhancing photocatalytic performance, which should be attributed to the fact that the heterostructure usually has smaller bandgap than the single semiconductor, and the formation of the built‐in electric field in the heterostructure interface area can hinder photogenerated carriers.…”

Hybrid Density Functional Study on the Photocatalytic Properties of Two-dimensional g-ZnO Based Heterostructures

“…Recently, graphene-like ZnO (g-ZnO) has been experimentally synthesized [ 10 , 11 ] and proven to be energetically stable by density functional theory (DFT) [ 12 ]. Though there have been many investigations [ 13 , 14 , 15 , 16 ] focused on the magnetism of g-ZnO, few studies exist regarding the water-splitting [ 17 , 18 ] of g-ZnO. As bulk ZnO-based materials are promising water-splitting photocatalysts, we may wonder about the photocatalytic activity of g-ZnO- and g-ZnO-based materials.…”

Construction of 2D‐ZnS@ZnO Z‐Scheme Heterostructured Nanosheets with a Highly Ordered ZnO Core and Disordered ZnS Shell for Enhancing Photocatalytic Hydrogen Evolution

“…The hydrogen production rate constants are 26.28, 34.13, and 26.26 min À 1 , corresponding to OS6-60-2, OS6-60-6, and OS6-60- 7)). 12, respectively. Figure 8c shows the effect of synthesis temperature on the photocatalytic hydrogen production activity of ZnS@ZnO nanosheets, and the intermediate temperature of 60°C is the optimal one.…”

“…Besides, the ZnO exhibits poor stability in acidic or basic environments, which limits its applications. Many attempts are taken to improve the photocatalytic performance of ZnO . Broadening the light response and improving the separation efficiency of photogenerated charge carriers are two key aspects.…”

“…Many attempts are taken to improve the photocatalytic performance of ZnO. [9][10]11,12,13,14] Broadening the light response and improving the separation efficiency of photogenerated charge carriers are two key aspects. Formation of heterostructure is an efficient way to improve the separation of charge carriers, resulting in the enhanced photocatalytic performance.…”