Prolonged exposure to n-butanol, a common hazardous volatile organic compound(VOC) in the environment, can lead to a broad range of adverse health effects. Therefore, detecting n-butanol safely and efficiently at low ...Prolonged exposure to n-butanol, a common hazardous volatile organic compound(VOC) in the environment, can lead to a broad range of adverse health effects. Therefore, detecting n-butanol safely and efficiently at low concentrations becomes critical for both environmental monitoring and human health. In this study, a novel Eu/Ce-codoped MOF-ZnO gas sensor was developed for the sensitive detection of n-butanol gas under ultraviolet activation at ambient temperature. A series of Eu/Ce-ZnO nanomaterials were synthesized via a simple co-precipitation route, by carefully designing the varied mass ratios of Eu and Ce incorporated into pristine ZnO derived from MOF precursors. The gas testing results revealed that introducing an appropriate amount of Eu and Ce would enlarge the specific surface area and enrich the oxygen vacancy content compared to pristine MOF-ZnO. Upon UV irradiation, the 0.03 wt% Eu 0.04 wt% Ce-ZnO sensor achieved a superior response of 611 for100 ppm n-butanol at room temperature, 15.28 times higher than that of pristine MOF-ZnO(40). Furthermore, the sensor presented rapid response/recovery times(15 s/28 s) and excellent selectivity. The above contributions pave the way for the promising development of highly sensitive, ultraviolet-enhanced gas sensors for ambient temperature detection of VOCs.展开更多
The large and dense rare earth (RE)-oxide inclusions in high-oxygen RE metal increase the risk of producing variable properties in RE steel. Consequently, a self-developed electrolysis cell was utilized for the produc...The large and dense rare earth (RE)-oxide inclusions in high-oxygen RE metal increase the risk of producing variable properties in RE steel. Consequently, a self-developed electrolysis cell was utilized for the production of low-oxygen La/Ce mischmetal. The electrolysis process and the origin of oxygen in mischmetal were comprehensively investigated. The results indicate that the reaction between La/Ce oxide and fluoride molten salt results in the formation of La/Ce oxy-fluoride. The deposition of oxy-fluoride at the bottom of the electrolysis cell is the primary factor contributing to the increased oxygen content in mischmetal. The comprehensive influence of oxide addition quantity, feeding interval, and electrolysis temperature on oxygen content, purity, and current efficiency using the response surface methodology model is revealed. The results for industrial experiment show that the purity of mishcmetal reaches higher than 99.78 wt.%, the oxygen content of mischmetal is only 0.0047 wt.% and the current efficiency of the electrolysis process achieves 80.79% under the optimized parameters of 225 kg/d, 30 s and 1069 ℃. The findings offer valuable insights into the application of molten salt electrolysis for the production of low-oxygen mischmetal.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 12304467)the China Postdoctoral Science Foundation (Grant No. 2023M732175)。
文摘Prolonged exposure to n-butanol, a common hazardous volatile organic compound(VOC) in the environment, can lead to a broad range of adverse health effects. Therefore, detecting n-butanol safely and efficiently at low concentrations becomes critical for both environmental monitoring and human health. In this study, a novel Eu/Ce-codoped MOF-ZnO gas sensor was developed for the sensitive detection of n-butanol gas under ultraviolet activation at ambient temperature. A series of Eu/Ce-ZnO nanomaterials were synthesized via a simple co-precipitation route, by carefully designing the varied mass ratios of Eu and Ce incorporated into pristine ZnO derived from MOF precursors. The gas testing results revealed that introducing an appropriate amount of Eu and Ce would enlarge the specific surface area and enrich the oxygen vacancy content compared to pristine MOF-ZnO. Upon UV irradiation, the 0.03 wt% Eu 0.04 wt% Ce-ZnO sensor achieved a superior response of 611 for100 ppm n-butanol at room temperature, 15.28 times higher than that of pristine MOF-ZnO(40). Furthermore, the sensor presented rapid response/recovery times(15 s/28 s) and excellent selectivity. The above contributions pave the way for the promising development of highly sensitive, ultraviolet-enhanced gas sensors for ambient temperature detection of VOCs.
基金supported by the National Natural Science Foundation of China(No.52101165)the Inner Mongolia Science and Technology Major Project(No.2020ZD0010)the Key Research Program of the Chinese Academy of Sciences(No.ZDRW-CN-2021-3).
文摘The large and dense rare earth (RE)-oxide inclusions in high-oxygen RE metal increase the risk of producing variable properties in RE steel. Consequently, a self-developed electrolysis cell was utilized for the production of low-oxygen La/Ce mischmetal. The electrolysis process and the origin of oxygen in mischmetal were comprehensively investigated. The results indicate that the reaction between La/Ce oxide and fluoride molten salt results in the formation of La/Ce oxy-fluoride. The deposition of oxy-fluoride at the bottom of the electrolysis cell is the primary factor contributing to the increased oxygen content in mischmetal. The comprehensive influence of oxide addition quantity, feeding interval, and electrolysis temperature on oxygen content, purity, and current efficiency using the response surface methodology model is revealed. The results for industrial experiment show that the purity of mishcmetal reaches higher than 99.78 wt.%, the oxygen content of mischmetal is only 0.0047 wt.% and the current efficiency of the electrolysis process achieves 80.79% under the optimized parameters of 225 kg/d, 30 s and 1069 ℃. The findings offer valuable insights into the application of molten salt electrolysis for the production of low-oxygen mischmetal.
