Yi Yang,Jingjing Liu,Miaoli Gu,Bei Cheng,Linxi Wang,Jiaguo Yu
Coupling photocatalytic H 2 O 2 evolution with simultaneous furfuryl alcohol oxidation can avoid the slow water oxidation reaction and fully utilize photogenerated carriers to produce valuable chemicals. Herein, a COF (denoted as BTTA) was synthesized by the Schiff-base condensation and in-situ grown on the surface of TiO 2 nanofibers. The resultant TiO 2 /BTTA composite has a large interface and a short carrier migration distance. Furthermore, the porous and ultrathin BTTA layers endow the composites abundant active sites and excellent light absorption ability. Remarkably, a H 2 O 2 -evolution rate of 740 μmol L −1 h −1 and a furoic alcohol conversion of 96 % are achieved. In-situ irradiated X-ray photoelectron spectroscopy and electron spin resonance confirm the S-scheme carrier transfer mechanism, which spatially separates photogenerated carriers with strong redox power. This work opens a new door to the rational design of S-scheme photocatalysts for economic and green photosynthesis of H 2 O 2 and organic compounds.
Ma Wanwan,Chen Huan,Hou Hongwei,Hu Qingyuan,Bai Yu
Phosphatidylcholine (PC) and lysophosphatidylcholine (LPC), two types of phospholipids (PLs), have been reported to be closely correlated with head and neck cancers of laryngeal cancer (LC) and thyroid cancer (TC), which make their analysis crucial. TiO 2 @COF-based solid-phase microextraction (SPME) coupled to UHPLC-MS/MS was developed for the rapid and accurate detection of seven potential PL biomarkers from small amounts of serum in this work. The combination of TiO 2 and COF proves to be effective for the extraction of the target analytes. Under optimal conditions, the developed TiO 2 @COF-based SPME-UHPLC-MS/MS method revealed good linearity ( R 2 ≥ 0.997) with LODs ranging from 0.05 to 0.38 ng/mL for PLs, the extraction recoveries and matrix effects ranging from 83.09–112.03% and 85.38–113.67%, respectively. As a high-throughput pretreatment method, satisfactory probe-to-probe reproducibility rates of 2.7–10.1% were obtained. Finally, the TiO 2 @COF-based SPME-UHPLC-MS/MS method was applied to analyze LPC 14:0, LPC 16:0, LPC 18:0, LPC 18:1, LPC 19:0, PC 16:0/18:1, and PC 18:0 in serum samples from early LC patients ( n = 15), early TC patients ( n = 15), and healthy volunteers ( n = 15). The results indicated that cancer patients could be effectively differentiated from healthy controls using orthogonal partial least squares discriminant analysis (OPLS-DA). In conclusion, the established TiO 2 @COF-based SPME-UHPLC-MS/MS method is reliable for the rapid determination of the seven PLs in serum samples, which is promising for early diagnosis of head and neck cancers. Graphical abstract
To construct the heterojunctions of TiO 2 with other compounds is of great importance for overcoming its inherent shortages and improving the visible-light photocatalytic performance. Here we propose the construction of TiO 2 /covalent organic framework (COF) heterojunction with tight connection by a supercritical CO 2 (SC CO 2 ) method, which helps bridging the transformation paths for photo-induced charge between TiO 2 and COF. The produced TiO 2 /COF heterojunction performs a H 2 evolution of 3,962 µmol·g −1 ·h −1 under visible-light irradiation, which is ∼ 25 times higher than that of pure TiO 2 and 4.5 folds higher than that of TiO 2 /COF synthesized by the conventional solvothermal method. This study opens up new possibilities for constructing heterojunctions for solar energy utilization.
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