ZrO2-Based Photocatalysts for Wastewater Treatment: From Novel Modification Strategies to Mechanistic Insights

Abstract

Zirconium dioxide (ZrO2) has garnered substantial research interest in the field of photocatalytic water treatment due to its appealing properties, such as thermal stability, considerable physical strength, and strong chemical resistance. However, the wide bandgap energy endorses less photoabsorption and rapid charge carrier recombination kinetics, thus restricting the photoactivity of ZrO2. Previously, vast research efforts have been made to improve the photoefficacy of ZrO2, and hence it is worth exploring the potential strategic modifications responsible for incremented photocatalytic efficiency. In this regard, the present review article emphasizes the optical, structural, and electronic features of ZrO2, which makes it an interesting photocatalytic material. The exceptional modification strategies that help to modulate the crystal structure, morphology, bandgap energy, and charge carrier kinetics are primarily discussed. The potential synthetic routes involving bottom-up and top-down methods are also outlined for understanding the rationale for incorporating these techniques. Moreover, the photocatalytic performance evaluation was done by investigating the photodegradation kinetics of various organic and inorganic pollutants degradation by ZrO2. Conclusively, in light of research advances involving ZrO2 photocatalyst, this review article may expedite further investigation for enhancing the large-scale photocatalytic applications for environmental and energy concerns.

Structural changes in HfSe2and ZrSe2thin films with various oxidation methods

“…Based on measurements of the fast Fourier transform of the images, amorphous HfO 2 and ZrO 2 are reorganized into a crystal structure that is consistent with the P 2 1 / c structure reported in the literature. 32,33 The change of structure is observed at 250–300 °C. This is consistent with previous reports 34,35 in which transitions to a crystalline structure at elevated temperatures have been observed for amorphous HfO 2 and ZrO 2 on a crystalline substrate.…”

Ultraviolet Exposure Improves SERS Activity of Graphene-Coated Ag/ZrO2 Substrates

“…Zirconia is known as a WBG semiconductor, which possesses photocatalytic activity [44]. In our study, we aimed to ascertain whether the granular ZrO 2 block imparts the self-cleaning property to the SERS-active substrate facilitated by the UV exposure and if the graphene coating enables an improvement of this property.…”

“…The enhanced efficacy of the shorter wavelength UV light is attributable to its deeper penetration and interaction with the internal zirconia grains, while the near-UV primarily engages the surface layer [27]. The short-wavelength UV is hardly absorbed by zirconia [27] thus interacting just with the surface zirconia structures, while longer UV waves are well-absorbed thanks to the rather wide bandgap [44]. Therefore, 254 nm irradiation would interact with in-depth volume of the zirconia sample, which provides more zirconia crystals compared to the surface layer.…”

Functional hBN decorated Ni(OH)2 nanosheets synthesized for remarkable adsorption performance for the elimination of fluoride ions

“…The world faces various obstacles in providing clean and safe drinking water because of natural activities and man-led activities like the release of hazardous chemicals into the environment from industries; therefore, water resources are constantly contaminated. 1 In drinking water, fluoride is one of the contaminants that is hazardous to human health if it is present in a concentration above the permissible limit recommended by the WHO guideline of 1.5 mg L −1 . 2 Fluoride concentrations in drinking water are high in over 35 nations worldwide, particularly China, India, Pakistan, South Africa, Turkey, Argentina, and Mexico.…”