Giles Spencer L, Kastl Anastasia M, Purdy Andrew P, Leff Asher C, Ratchford Daniel C, Maza William A, Baturina Olga A
Chemistry Division, United States Naval Research Laboratory, Washington, D.C. 20375, United States.
NREIP Intern, Chemistry Division, United States Naval Research Laboratory, Washington, D.C. 20375, United States.
ACS Appl Mater Interfaces. 2022 Feb 23;14(7):9655-9666. doi: 10.1021/acsami.1c18180. Epub 2022 Feb 8.
Robust materials capable of heterogeneous reactivity are valuable for addressing toxic chemical clean up. Synthetic manipulations for generating titanium oxide nanomaterials have been utilized to alter both photochemical (1000 nm > λ > 400 nm) and chemical heterogeneous reactivity with 2-chloroethyl ethyl sulfide (2-CEES). Synthesizing TiO nanomaterials in the presence of long-chain alkylphosphonic acids enhanced the visible light-driven oxidation of the thioether sulfur of 2-CEES. Photooxidation reaction rates of 99 and 168 μmol/g/h (quantum yields of 5.07 × 10 and 8.58 × 10 molecules/photon, respectively) were observed for samples made with two different alkylphosphonic acids (CHPOH and CHPOH, respectively). These observations are correlated with (i) generation of new surface defects/states (i.e., oxygen vacancies) as a result of TiO grafting by alkylphosphonic acid that may serve as reaction active sites, (ii) better light absorption by assemblies of nanorods and nanowires in comparison to individual nanorods, (iii) surface area differences, and (iv) the exclusion of OH groups due to the surface functionalization with alkylphosphonic acids via Ti-O-P bonds on the TiO. Alternatively, nanowire-form HTiO·HO was produced and found to be capable of highly efficient hydrolysis of the carbon-chlorine (C-Cl) bond of 2-CEES in the dark with a reaction rate of 279.2 μmol/g/h due to the high surface area and chemical nature of the titanate structure.
具有非均相反应活性的坚固材料对于解决有毒化学物质的清理问题很有价值。用于生成二氧化钛纳米材料的合成操作已被用于改变光化学（1000 nm > λ > 400 nm）和与2-氯乙基乙基硫醚（2-CEES）的化学非均相反应活性。在长链烷基膦酸存在下合成TiO纳米材料可增强2-CEES硫醚硫的可见光驱动氧化。对于用两种不同烷基膦酸（分别为CHPOH和CHPOH）制成的样品，观察到光氧化反应速率分别为99和168 μmol/g/h（量子产率分别为5.07×10和8.58×10分子/光子）。这些观察结果与以下因素相关：（i）由于烷基膦酸接枝TiO而产生新的表面缺陷/状态（即氧空位），这些缺陷/状态可能作为反应活性位点；（ii）与单个纳米棒相比，纳米棒和纳米线组装体具有更好的光吸收；（iii）表面积差异；（iv）由于通过TiO上的Ti-O-P键用烷基膦酸进行表面功能化而排除了OH基团。另外，制备了纳米线形式的HTiO·HO，发现由于钛酸盐结构的高表面积和化学性质，它能够在黑暗中高效水解2-CEES的碳-氯（C-Cl）键，反应速率为279.2 μmol/g/h。
