In the hydrogenation of polyfunctional compounds, achieving high selectivity for specific functional groups remains challenging. Herein we report that SiC quantum dots (QDs) can selectively adsorb C = O in cinnamaldehyde, significantly increasing the activity and selectivity of Pt/SiC for hydrogenating cinnamaldehyde to cinnamyl alcohol. A 10 wt% QDs-modified Pt/SiC catalyst showed a turnover frequency 3.5 times higher than Pt/SiC under mild conditions. Further studies reveal that the defect-rich surface of SiC QDs facilitates the adsorption of C = O bond in cinnamaldehyde and enhances the spillover of active hydrogen from Pt to SiC QDs. During the catalysis process, Pt is responsible for the generation of reactive hydrogen species while the QDs undertake the activation of C = O bond, and the hydrogen species react with cinnamaldehyde via spillover. This work demonstrates the promise of SiC QDs in heterogeneous catalysis and provides a reference for designing novel hydrogenation catalysts.
Yao Wenyan,Shi Jian,Ling Jiang,Guo Yadong,Ding Chensen,Ding Yanjun
Aptamer-modified SiC quantum dots (DNA-SiC QDs) as fluorescent aptasensor are described for the determination of Proteus mirabilis . The SiC QDs were synthesized through one-pot hydrothermal method with particle sizes of about 14 nm. The amino-modified aptamers against P. mirabilis were conjugated to the surfaces of SiC QDs for bacteria recognition . The aptamer with an affinity for target protein can bound to P. mirabilis and this causes a decrease in the fluorescence intensity of DNA-SiC QDs. P. mirabilis levels were tested by the aptasensor within 35 min with fluorescence excitation/emission maxima at 320/420 nm. The linear range is from 10 3 to 10 8 CFU mL −1 and the limit of detection is 526 CFU mL −1 ( S / N = 3). The aptasensor was used for determination of P. mirabilis in pure milk samples and obtained good accuracy (87.6–104.5%) and recovery rates (85–110.2%) were obtained. The detection in simulated forensic identification samples (pure milk, milk powder, blood, and urine) obtained gave satisfactory coincidence rates with the method of bacterial isolation and identification as standard. These results demonstrate that the fluorescent aptasensor is a potential tool for identification of P. mirabilis in forensic food poisoning cases.
Determination of P. mirabilis is based on SiC QDs fluorescence aptasensor. The SiC QDs with plentiful carboxyl groups on the surface can be synthesized via one-pot hydrothermal route. After activated by EDC/NHS, the SiC QDs can bind to aptamer to form fluorescence aptasensors. When the target P. mirabilis exists, the fluorescence of aptasensor will be quenched and the determination of the P. mirabilis based on the fluorescence change can be analyzed.
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