Lewis Acid-Base Interaction Triggering Electron Delocalization to Enhance the Photodegradation of Extracellular Antibiotic Resistance Genes Adsorbed on Clay Minerals

The transformation of extracellular antibiotic resistance genes (eARGs) is largely influenced by their inevitable photodegradation in environments where they tend to be adsorbed by ubiquitous clay minerals instead of being in a free form. However, the photodegradation behaviors and mechanisms of the adsorbed eARGs may be quite different from those of the free form and still remain unclear. Herein, we found that kaolinite, a common 1:1-type clay, markedly enhanced eARG photodegradation and made eARGs undergo direct photodegradation under UVA. The decrease in the transformation efficiency of eARGs caused by photodegradation was also promoted. Spectroscopy methods combined with density functional theory calculations revealed that the Lewis acid-base interaction between P-O in eARGs and Al-OH on kaolinite delocalized electrons of eARGs, thus resulting in increased photon absorption ability of eARGs. This ultimately led to enhanced photodegradation of kaolinite-adsorbed eARGs. Additionally, divalent Ca²⁺ could reduce the Lewis acid-base interaction-mediated adsorption of eARGs by kaolinite, thereby weakening the enhanced photodegradation of eARGs caused by electron delocalization. In contrast, the 2:1-type clay montmorillonite without strong Lewis acid sites was unable to delocalize the electrons to enhance the photodegradation of eARGs. This work allowed us to better evaluate eARGs' fate and risk in real aqueous environments.

2,2'-Dihydroxy-4,4'-dimethoxy-benzophenon as Bifunctional Additives for Passivated Defects and Improved Photostability of Efficient Perovskite Photovoltaics

Organic-inorganic hybrid perovskite solar cells (PSCs) have developed rapidly in the past decade, but their commercial applications are restricted by further improvement in their photovoltaic performance and stability. Herein, we propose a facile and effective method employing 2,2'-dihydroxy-4,4'-dimethoxy-benzophenon (BP6) as bifunctional additive to construct efficient and photostable PSCs. BP6, as an additive, improves the crystallization quality of perovskite absorbers and further inhibits defect-mediated non-radiative recombination through interaction between the C═O group and defects; as a UV absorber, BP6 protects the PSCs from UV degradation by effectively absorbing UV light through molecular tautomerism under continuous strong UV irradiation. Eventually, the champion PSC demonstrates an efficiency of 22.85% with enhanced UV stability after addition of 0.024 wt % BP6. These results reveal that addition of UV absorbers (such as BP6 in this study) is a simple and effective strategy to fabricate efficient and photostable PSCs.