Origin and Electronic Features of Reactive Oxygen Species at Hybrid Zirconia-Acetylacetonate Interfaces

Abstract

The hybrid sol-gel zirconia-acetylacetonate amorphous material (HSGZ) shows high catalytic activity in oxidative degradation reactions without light or thermal pretreatment. This peculiar HSGZ ability derives from the generation of highly reactive oxygen radical species (ROS) upon exposure to air at room conditions. We disclose the origin of such unique feature by combining EPR and DRUV measurements with first-principles calculations. The organic ligand acetylacetonate (acac) plays a pivotal role in generating and stabilizing the superoxide radical species at the HSGZ-air interfaces. Our results lead the path toward further development of HSGZ and related hybrid materials for ROS-based energy and environmental applications.

Metal Acetylacetonate Series in Interface Engineering for Full Low‐Temperature‐Processed, High‐Performance, and Stable Planar Perovskite Solar Cells with Conversion Efficiency over 16% on 1 cm2 Scale

“…Metal acetylacetonates series has high pyrolysis temperature, for example, 197 °C for ZrAcac, [65] and also has high hyrolysis threshold owing to that Acac group has strong chelate bonding to Zr(IV) ions, which is insensitive to water and chemicals. [66] These merits of metal acetylacetonates have the potential of expanding the process windows for PSCs. Additionally, the hydrolysis and pyrolysis products of metal acetylacetonates, such as ZrO 2 or ZrO 2 (OH) x , are also very stable and hold high dielectric constant for passivating the interface of PSCs.…”

Photosensitive Hybrid Nanostructured Materials: The Big Challenges for Sunlight Capture

“…The final hybrid TiO 2 -melanin nanostructures have shown excellent antimicrobial activity even without irradiation, owing to their ability in generating reactive oxygen species (ROS) [140][141][142][143]. Another interesting family of compounds, yet still poorly studied in the frame of CT complexes, are β-diketones: acetylacetone (2,4-pentanedione) has been shown to considerably shift the absorption onset of TiO 2 [101,144] and ZrO 2 [145] through LMCT. Moreover, hybrid oxide-acetylacetonate materials prepared by a sol-gel procedure exhibit the peculiar ability to generate and stabilize on their surface the superoxide radical anion (a pivotal ROS), with a consequent activity in organic pollutants degradation even in the dark [144][145][146][147].…”

“…Another interesting family of compounds, yet still poorly studied in the frame of CT complexes, are β-diketones: acetylacetone (2,4-pentanedione) has been shown to considerably shift the absorption onset of TiO 2 [101,144] and ZrO 2 [145] through LMCT. Moreover, hybrid oxide-acetylacetonate materials prepared by a sol-gel procedure exhibit the peculiar ability to generate and stabilize on their surface the superoxide radical anion (a pivotal ROS), with a consequent activity in organic pollutants degradation even in the dark [144][145][146][147]. In most reports, sensitized hybrid materials are prepared by surface adsorption on commercial or synthesized TiO 2 nanoparticles, whereas LMCT sensitized thin films have been seldom investigated, besides some TiO 2 coatings whose surface was functionalized with catechol [126,148].…”

“…Only some studies on the interaction of ZnO with sensitizing ligands were found, e.g., with catechol [152], 1,2-dihydroxynaphthalene, and 8-hydroxyquinoline [131], or dopamine and modified catechol with porphyrins [153]. ZrO 2 and Fe 2 O 3 were previously proven to extend their absorption bands following the adsorption of dopamine, ascorbic acid, and alizarin [98]; no recent updates regarding direct sensitization of these oxides were found, although amorphous ZrO 2 complexed with acetylacetone showed absorption extended up to the visible range [145]. Niobium oxide (Nb 2 O 5 ) has been proposed as a photocatalyst as well, and its photoactivity with visible light has been connected with the formation of LMCT with the substrates.…”

Ion specificity in determining physico-chemical properties of drinking water

“…On turn, the interfacial energy is determined by the surface tension of the two phases put in contact (Marmur & Valal, 2010;Muñoz-García et al, 2015). The liquid surface tension is determined by the solutes content that is related to diet (Paßlack et al, 2014) and, especially in a regime of increased water intake, to drinking water (Toxqui & Vaquero, 2016;Schwartz et al, 2002).…”