An optical fiber toluene gas sensor working at room temperature is proposed based on CQDs@SiO 2 (-OH) porous film. The CQDs@SiO 2 (-OH) porous film was elaborated on the surface of the hollow core fiber (HCF) using the templating method, where the evanescent field is excited by a misaligned structure. The precursor solution formed by mixing CQDs with SiO 2 (-OH) enhances CQDs dispersion within the film, preventing aggregation and preserving active sites. Experimental results indicate that the gas-sensitive layer doped with CQDs demonstrates a sensitivity of 5.1 pm/ppm to toluene gas at room temperature, which is approximately 3.13 times greater than that of the SiO 2 (-OH) porous film. Additionally, it demonstrates a response time of 12 s and a limit of detection (LOD) of 3.9 ppm. The gas sensing mechanism is thoroughly investigated using DFT, exploring the electronic distribution of the gas-sensitive layer before and after CQDs doping and analyzing the sensitization mechanism. This study presents a novel approach for toluene gas detection at room temperature using an optical fiber sensor.
High-entropy perovskite catalyst was synthesized and utilized for the first time in the MSR catalytic reaction. Among the HEPs, La(CoCuFeAlCe) 0.2 O 3 exhibited excellent MSR activity and high selectivity. The mechanism of the MSR reaction on the catalyst (100) surface was studied by employing DFT. The results indicate that the surface of La(CoCuFeAlCe) 0.2 O 3 catalyst has the lowest energy barrier, where the aldehyde hydrogenation reaction is the rate-determining step, explaining its high activity and selectivity. This research contributes additional evidence for the creation of high-entropy perovskite catalysts for MSR.
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