Defect-rich ZnO nanosheets of high surface area as an efficient visible-light photocatalyst

Abstract

A facile ultra-rapid solution method was developed to fabricate ZnO nanosheets with tunable BET surface area and rich oxygen-vacancy defects. The addition of 1 molL-1 Na 2 SO 4 led to an increase of BET surface area of ZnO nanosheets from 6.7 to 34.5 m 2 /g, through an electrostatic-controlled growth and self-assembly mechanism. Detailed analysis based on Raman scattering, room-temperature photoluminescence, X-ray photoelectron spectroscopy and electron spin resonance revealed that the as-prepared ZnO nanosheets were rich in oxygen-vacancies. Increased BET surface area led to a further increase of surface oxygen-vacancy concentration. The rich oxygen-vacancies promoted the visible-light absorption of the ZnO nanosheets, leading to high photocurrent responses and photocatalytic activities towards the degradation of rhodamine B (apparent rate constants, k=0.0179 min-1) under visible-light illumination (>420 nm), about 13 and 11 times higher, respectively than that of ZnO nanoparticles with few oxygen defects. In addition, the high-surface-area ZnO nanosheets could be effectively hybridized with Ag 3 PO 4 nanoparticles, resulting in a further enhancement of the visible-light photocatalytic performance (k=0.0421 min-1).

Facile approach for synthesis of stable, efficient, and recyclable ZnO through pulsed sonication and its application for degradation of recalcitrant azo dyes in wastewater

“…The surface area of the synthesized ZnO particles were found to be 3.93 m 2 /g ( Fig. 8), approximately equals to the surface area of ZnO nanoparticles reported earlier [35]. The ZnO agglomerated assemblies with sufficient surface area and more mesoporous structures also acts as adsorbents while used for the treatment of dye pollutants.…”

The Applications of Morphology Controlled ZnO in Catalysis

“…The fraction of polar facets increased with the increase of the Bi 2 WO 6 mass ratio which led to a more efficient separation efficiency of photo-generated charge carriers or a longer lifetime of the photo-excited electron-hole pairs, enhancing the photo-degradation efficiency of RhB. Later, Wang et al successfully synthesized defect-rich ZnO nanosheets with high surface area and investigated the photo degradation performance of RhB under visible-light illumination (λ > 420 nm) [221]. The ZnO nanosheet with rich oxygen-vacancies exhibited enhanced photocatalytic activities, about 11 times higher than that of ZnO nanoparticles with few oxygen-vacancies.…”

Photoexcited Properties of Tin Sulfide Nanosheet-Decorated ZnO Nanorod Heterostructures

“…However, the wide bandgap of ZnO significantly restricts its use under solar light because only a limited percentage of solar radiation is within the ultraviolet (UV) range. Several methods, such as crystal defect density control and chemical composition modification of ZnO nanostructures, have been adopted to improve the solar light-harvesting efficiency of ZnO [7, 8] and have produced limited improvements of the light-harvesting efficiency of ZnO. The efficiency levels of photoexcited devices made from ZnO nanostructures under solar light irradiation still require substantial improvement.…”