Jiahong Wen,Yaxin Wang,Ruoning Chu,Jinhai Li,Ze Chen,Yongjun Zhang,Xiaoyu Zhao,Qi-Qi Fu
Freon refrigerants, whose leakage will cause serious safety and environmental issues, have an urgent need of developing leakage detection technologies. Conventional metal oxide semiconductor (MOS) gas sensors exhibit limited efficacy in detecting halogenated Freons due to their chemical inertness and weak charge-transfer interactions. While recent innovations employing mesoporous γ-Al 2 O 3 overlayers have enabled Freon detection via catalytic decomposition sensing mechanism, the achieved sensing performance remains suboptimal. In this work, this issue is addressed by engineering a Pd-doped mesoporous γ-Al 2 O 3 /SnO 2 (Pd-γ-Al 2 O 3 /SnO 2 ) gas sensor. The doped Pd atoms not only accelerate the decomposition of Freon molecules on the catalytic layer but also induce the Schottky-barrier effect in the SnO 2 sensing layer. Benefiting from the synergistic effect, the Pd-γ-Al 2 O 3 /SnO 2 gas sensor shows outstanding response, good stability, repeatability, selectivity, and rarely-reported universality in sensing different Freon gases. Notably, a valuable solution is demonstrated in the leakage detection of next-generation refrigerants, Freon R1234yf. The sensing mechanism is deduced by exhaust gas components identification. These results highlight the promising potential for addressing the real-world needs of Freon refrigerant leakage detection technology.
Zhuangpeng Huang,Zhiping Chen,Yuancai Chen,Yongyou Hu
Iron-copper bimetal supported on mesoporous γ-Al 2 O 3 with different Fe/Cu ratios was prepared via a modified evaporation-induced self-assembly method and employed to degrade 4-chlorophenol (4-CP) in a Fenton-like process. The X-ray photoelectron spectroscopy, X-ray diffraction spectrum and UV–vis diffuse reflectance spectroscopy results confirmed the co-doping of Fe 2+ /Fe 3+ and Cu + /Cu 2+ into the lattice of γ-Al 2 O 3 through the bonds of Al O Fe and Al O Cu. With the iron and copper co-doped in γ-Al 2 O 3 , three-fold oxygen vacancies (V 0 ) could be achieved compared with that of non-metal catalysts, which was favorable for the reduction of iron and copper species. The 1Fe3Cu-γ-Al 2 O 3 with a Fe/Cu mass ratio of 1:3 exhibited the highest activity on Fenton-like degradation of 4-CP due to the synergistic effects of Fe and Cu by facilitating the electron transfer in the recycles of Cu + /Cu 2+ and Fe 2+ /Fe 3+ based on the results of X-ray photoelectron spectroscopy, cyclic voltammetry and electro paramagnetic resonance analysis. The utilization efficiency of H 2 O 2 was as high as 86.0% when 4-CP almost disappeared (i.e., 99.7 percent of 0.78 mM 4-CP) at 240 min and pH 7.0, additionally, their dechlorination and TOC removal efficiencies were 92.0% and 81.6%, respectively. The catalyst also displayed a good performance after 5th cycles. Furthermore, a possible mechanism for activation of OH on the catalyst surface was also proposed.
危险品化学品经营许可证（带存储）