Nitric oxide （NO） deep oxidation to dinitrogen pentoxide （N2O5） by ozone together with wet scrub-bing has become a promising technology for nitrogen-oxide （NOx） removal in industrial boilers. Catalysts wer...Nitric oxide （NO） deep oxidation to dinitrogen pentoxide （N2O5） by ozone together with wet scrub-bing has become a promising technology for nitrogen-oxide （NOx） removal in industrial boilers. Catalysts were introduced to enhance the N2O5 formation rate with less ozone injection and leakage. A series of monometallic catalysts （manganese, cobalt, cerium, iron, copper, and chromium） as pre-pared by the sol-gel method were tested. The manganese oxides achieved an almost 80% conver-sion efficiency at an ozone （O3）/NO molar ratio of 2.0 in 0.12 s. The crystalline structure and porous parameters were determined. The thermodynamic reaction threshold of NO conversion to N2O5 is oxidation with an O3/NO molar ratio of 1.5. Spherical alumina was selected as the support to achieve the threshold, which was believed to improve the catalytic activity by increasing the surface area and the gas-solid contact time. Based on the manganese oxides, cerium, iron, chromium, cop-per, and cobalt were introduced as promoters. Cerium and iron improved the deep-oxidation effi-ciency compared with manganese/spherical alumina, with less than 50 mg/m3 of outlet NO ＋ nitro-gen oxide, and less than 25 mg/m3 of residual ozone at an O3/NO molar ratio of 1.5. The other three metal oxides inhibited catalytic activity. X-ray diffraction, nitrogen adsorption, hydrogen tempera-ture-programmed reduction, and X-ray photoelectron spectroscopy results indicate that the cata-lytic activity is affected by the synergistic action of NOx oxidation and ozone decomposition.展开更多
A series of SnO2‐based catalysts modified by Mn, Zr, Ti and Pb oxides with a Sn/M （M=Mn, Zr, Ti and Pb） molar ratio of 9/1 were prepared by a co‐precipitation method and used for CH4 and CO oxidation. The Mn3＋, ...A series of SnO2‐based catalysts modified by Mn, Zr, Ti and Pb oxides with a Sn/M （M=Mn, Zr, Ti and Pb） molar ratio of 9/1 were prepared by a co‐precipitation method and used for CH4 and CO oxidation. The Mn3＋, Zr4＋, Ti4＋and Pb4＋cations are incorporated into the lattice of tetragonal rutile SnO2 to form a solid solution structure. As a consequence, the surface area and thermal stability of the catalysts are improved. Moreover, the oxygen species of the modified catalysts become easier to be reduced. Therefore, the oxidation activity over the catalysts was improved, except for the one modified by Pb oxide. Manganese oxide demonstrates the best promotional effects for SnO2. Using an X‐ray diffraction extrapolation method, the lattice capacity of SnO2 for Mn2O3 was 0.135 g Mn2O3/g SnO2, which indicates that to form stable solid solution, only 21%Sn4＋cations in the lattice can be maximally replaced by Mn3＋. If the amount of Mn3＋cations is over the capacity, Mn2O3 will be formed, which is not favorable for the activity of the catalysts. The Sn rich samples with only Sn‐Mn solid solution phase show higher activity than the ones with excess Mn2O3 species.展开更多
In-situ DRIFTS was used to study the deep oxidation of propane, a side reaction during propane oxidative dehydrogenation to propene. Strong adsorption of propene was supposed to be the main reason for the deep oxidati...In-situ DRIFTS was used to study the deep oxidation of propane, a side reaction during propane oxidative dehydrogenation to propene. Strong adsorption of propene was supposed to be the main reason for the deep oxidation. It was found that gaseous oxygen in the feed and the reaction temperature had great influence on the reaction. To obtain a relative high selectivity to propene, the reaction temperature should be maintained at 150-250℃ with a proper content of gaseous oxygen in the feed for a certain catalyst and some modifiers which could weaken the adsorption of propene on the catalyst surface would be favorable.展开更多
We present a study on the single event transient （SET） induced by a pulsed laser in different silicon-germanium （SiGe） heterojunction bipolar transistors （HBTs） with the structure of local oxidation of silicon ...We present a study on the single event transient （SET） induced by a pulsed laser in different silicon-germanium （SiGe） heterojunction bipolar transistors （HBTs） with the structure of local oxidation of silicon （LOCOS） and deep trench isolation （DTI）. The experimental results are discussed in detail and it is demonstrated that a SiGe HBT with the structure of LOCOS is more sensitive than the DTI SiGe HBT in the SET. Because of the limitation of the DTI structure, the charge collection of diffusion in the DTI SiGe HBT is less than that of the LOCOS SiGe HBT. The SET sensitive area of the LOCOS SiGe HBT is located in the eollector-substrate （C/S） junction, while the sensitive area of the DTI SiGe HBT is located near to the collector electrodes.展开更多
Degrading volatile organic compounds at low temperatures and active sites aggregation are still challenging.In this study,a novel mesoporous zeolite silicalite-1(S-1–meso)enveloped Pt–Ni bimetallic catalysts(noted a...Degrading volatile organic compounds at low temperatures and active sites aggregation are still challenging.In this study,a novel mesoporous zeolite silicalite-1(S-1–meso)enveloped Pt–Ni bimetallic catalysts(noted as Pt1Ni1@S-1–meso)were synthesized via a facile in situ mesoporous template-free method.The Pt–Ni bimetallic nanoparticles were uniformly distributed and displayed a large specific surface area and enriched mesopores to facilitate the deep oxidation of toluene.The presence of the Pt–Ni O interface both increased the dispersion of the catalyst and improved its catalytic performance,thereby reducing the consumption of Pt.The Mars-van Krevelen mechanism and density function theory(DFT)calculations revealed that the Pt–Ni O interface effect changed the electronic structure of Pt and Ni species,reduced the activation potential for oxygen,formed reactive oxygen species,and facilitated the adsorption and activation of reactants in the direction favorable to the toluene oxidation.This study provides a guideline for minimizing the proportion of precious metals used in practical applications and a promising method for toluene elimination at low temperatures.展开更多
Indole-3-carbinol(I3C),an important anticancer compound found in broccoli,has attracted considerable attention.The rapid extraction and accurate analysis of I3C in the pharmaceutical industry in broccoli is challengin...Indole-3-carbinol(I3C),an important anticancer compound found in broccoli,has attracted considerable attention.The rapid extraction and accurate analysis of I3C in the pharmaceutical industry in broccoli is challenging as I3C is unstable at low pH and high temperature.In this study,a rapid,accurate,and lowcost ultrasound-assisted dispersive-filter extraction(UADFE)technique based on poly(deep eutectic solvent)-graphene oxide(PDES-GO)adsorbent was developed for the isolation and analysis of I3C in broccoli for the first time.PDES-GO with multiple adsorption interactions and a fast mass transfer rate was synthesized to accelerate adsorption and desorption.UADFE was developed by combining dispersive solid-phase extraction(DSPE)and filter solid-phase extraction(FSPE)to realize rapid extraction and separation.Based on the above two strategies,the proposed PDES-GO-UADFE method coupled with high-performance liquid chromatography(HPLC)allowed the rapid(15-16 min),accurate(84.3%-96.4%),and low-cost(adsorbent:3.00 mg)analysis of I3C in broccoli and was superior to solid-phase extraction,DSPE,and FSPE methods.The proposed method showed remarkable linearity(r=0.9998;range:0.0840-48.0 mg/g),low limit of quantification(0.0840 mg/g),and high precision(relative standard deviation<5.6%).Therefore,the PDES-GO-UADFE-HPLC method shows significant potential in the field of pharmaceutical analysis for the separation and analysis of anti-cancer compounds in complex plant samples.展开更多
A series of(Ce,Cr)xO2/Nb2O5 catalysts with different(Ce,Cr)xO2 to Nb2O5 mass ratios were synthesized by the deposition-precipitation method for use in deep catalytic oxidation of 1,2-dichloroethane(DCE), which is one ...A series of(Ce,Cr)xO2/Nb2O5 catalysts with different(Ce,Cr)xO2 to Nb2O5 mass ratios were synthesized by the deposition-precipitation method for use in deep catalytic oxidation of 1,2-dichloroethane(DCE), which is one of the typical chlorinated volatile organic compound pollutants. The textural properties were characterized by X-ray diffraction, N2 adsorption/desorption isotherms, UV-Raman spectroscopy, and scanning electron microscopy. The surface acidity and the redox properties were characterized by ammonia temperature-programmed desorption and H2 temperature-programmed reduction, respectively. The results show that the addition of a proper amount of(Ce,Cr)xO2 over Nb2O5 significantly improves the intrinsic catalytic activity towards the deep oxidation of DCE, and only a very small amount of C2H3Cl is detected as the byproduct of the oxidation process. Further study reveals the existence of an obvious synergistic effect between Nb2O5, with abundant strong acid sites, and(Ce,Cr)xO2, with strong oxidation sites, as the strong acid sites of Nb2O5 promote the adsorption and dehydrochlorination of DCE, while the strong oxidation sites of(Ce,Cr)xO2 contribute to the deep oxidation of the reactant, intermediates, and byproducts.展开更多
基金supported by the National Natural Science Foundation of China(51422605)the Provincial Natural Science Foundation of Zhejiang,China(LR16E060001)~~
文摘Nitric oxide （NO） deep oxidation to dinitrogen pentoxide （N2O5） by ozone together with wet scrub-bing has become a promising technology for nitrogen-oxide （NOx） removal in industrial boilers. Catalysts were introduced to enhance the N2O5 formation rate with less ozone injection and leakage. A series of monometallic catalysts （manganese, cobalt, cerium, iron, copper, and chromium） as pre-pared by the sol-gel method were tested. The manganese oxides achieved an almost 80% conver-sion efficiency at an ozone （O3）/NO molar ratio of 2.0 in 0.12 s. The crystalline structure and porous parameters were determined. The thermodynamic reaction threshold of NO conversion to N2O5 is oxidation with an O3/NO molar ratio of 1.5. Spherical alumina was selected as the support to achieve the threshold, which was believed to improve the catalytic activity by increasing the surface area and the gas-solid contact time. Based on the manganese oxides, cerium, iron, chromium, cop-per, and cobalt were introduced as promoters. Cerium and iron improved the deep-oxidation effi-ciency compared with manganese/spherical alumina, with less than 50 mg/m3 of outlet NO ＋ nitro-gen oxide, and less than 25 mg/m3 of residual ozone at an O3/NO molar ratio of 1.5. The other three metal oxides inhibited catalytic activity. X-ray diffraction, nitrogen adsorption, hydrogen tempera-ture-programmed reduction, and X-ray photoelectron spectroscopy results indicate that the cata-lytic activity is affected by the synergistic action of NOx oxidation and ozone decomposition.
基金supported by the National Natural Science Foundation of China (21263015,21567016 and 21503106)the Education Department Foundation of Jiangxi Province (KJLD14005 and GJJ150016)the Natural Science Foundation of Jiangxi Province (20142BAB213013 and 20151BBE50006),which are greatly acknowledged by the authors~~
文摘A series of SnO2‐based catalysts modified by Mn, Zr, Ti and Pb oxides with a Sn/M （M=Mn, Zr, Ti and Pb） molar ratio of 9/1 were prepared by a co‐precipitation method and used for CH4 and CO oxidation. The Mn3＋, Zr4＋, Ti4＋and Pb4＋cations are incorporated into the lattice of tetragonal rutile SnO2 to form a solid solution structure. As a consequence, the surface area and thermal stability of the catalysts are improved. Moreover, the oxygen species of the modified catalysts become easier to be reduced. Therefore, the oxidation activity over the catalysts was improved, except for the one modified by Pb oxide. Manganese oxide demonstrates the best promotional effects for SnO2. Using an X‐ray diffraction extrapolation method, the lattice capacity of SnO2 for Mn2O3 was 0.135 g Mn2O3/g SnO2, which indicates that to form stable solid solution, only 21%Sn4＋cations in the lattice can be maximally replaced by Mn3＋. If the amount of Mn3＋cations is over the capacity, Mn2O3 will be formed, which is not favorable for the activity of the catalysts. The Sn rich samples with only Sn‐Mn solid solution phase show higher activity than the ones with excess Mn2O3 species.
基金supported by the National Natural Science Foundation of China (20576045)the Program for New Century Excellent Talentsin University (NCET-06-740)
文摘In-situ DRIFTS was used to study the deep oxidation of propane, a side reaction during propane oxidative dehydrogenation to propene. Strong adsorption of propene was supposed to be the main reason for the deep oxidation. It was found that gaseous oxygen in the feed and the reaction temperature had great influence on the reaction. To obtain a relative high selectivity to propene, the reaction temperature should be maintained at 150-250℃ with a proper content of gaseous oxygen in the feed for a certain catalyst and some modifiers which could weaken the adsorption of propene on the catalyst surface would be favorable.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61274106
文摘We present a study on the single event transient （SET） induced by a pulsed laser in different silicon-germanium （SiGe） heterojunction bipolar transistors （HBTs） with the structure of local oxidation of silicon （LOCOS） and deep trench isolation （DTI）. The experimental results are discussed in detail and it is demonstrated that a SiGe HBT with the structure of LOCOS is more sensitive than the DTI SiGe HBT in the SET. Because of the limitation of the DTI structure, the charge collection of diffusion in the DTI SiGe HBT is less than that of the LOCOS SiGe HBT. The SET sensitive area of the LOCOS SiGe HBT is located in the eollector-substrate （C/S） junction, while the sensitive area of the DTI SiGe HBT is located near to the collector electrodes.
基金supported by the National Natural Science Foundation of China(Nos.22276086,21976078)the Natural Science Foundation of Jiangxi Province(Nos.20202ACB213001,20232BCJ22003)。
文摘Degrading volatile organic compounds at low temperatures and active sites aggregation are still challenging.In this study,a novel mesoporous zeolite silicalite-1(S-1–meso)enveloped Pt–Ni bimetallic catalysts(noted as Pt1Ni1@S-1–meso)were synthesized via a facile in situ mesoporous template-free method.The Pt–Ni bimetallic nanoparticles were uniformly distributed and displayed a large specific surface area and enriched mesopores to facilitate the deep oxidation of toluene.The presence of the Pt–Ni O interface both increased the dispersion of the catalyst and improved its catalytic performance,thereby reducing the consumption of Pt.The Mars-van Krevelen mechanism and density function theory(DFT)calculations revealed that the Pt–Ni O interface effect changed the electronic structure of Pt and Ni species,reduced the activation potential for oxygen,formed reactive oxygen species,and facilitated the adsorption and activation of reactants in the direction favorable to the toluene oxidation.This study provides a guideline for minimizing the proportion of precious metals used in practical applications and a promising method for toluene elimination at low temperatures.
基金supported by the National Natural Science Foundation of China(Grant Nos.:82073605 and 81803287)the Natural Science Foundation of Hebei Province(Grant Nos.:B2018201270 and H2021201002)+3 种基金the Talent Engineering Training Foundation of Hebei Province(Grant No.:A201802002)the Research Project of Hebei Provincial Administration of Traditional Chinese Medicine(Grant No.:2021174)Post-graduate's Innovation Fund Project of Hebei University(Grant No.:HBU2021ss006)the Outstanding Doctoral Cultivation Project of Hebei University(Grant No.:YB201703).
文摘Indole-3-carbinol(I3C),an important anticancer compound found in broccoli,has attracted considerable attention.The rapid extraction and accurate analysis of I3C in the pharmaceutical industry in broccoli is challenging as I3C is unstable at low pH and high temperature.In this study,a rapid,accurate,and lowcost ultrasound-assisted dispersive-filter extraction(UADFE)technique based on poly(deep eutectic solvent)-graphene oxide(PDES-GO)adsorbent was developed for the isolation and analysis of I3C in broccoli for the first time.PDES-GO with multiple adsorption interactions and a fast mass transfer rate was synthesized to accelerate adsorption and desorption.UADFE was developed by combining dispersive solid-phase extraction(DSPE)and filter solid-phase extraction(FSPE)to realize rapid extraction and separation.Based on the above two strategies,the proposed PDES-GO-UADFE method coupled with high-performance liquid chromatography(HPLC)allowed the rapid(15-16 min),accurate(84.3%-96.4%),and low-cost(adsorbent:3.00 mg)analysis of I3C in broccoli and was superior to solid-phase extraction,DSPE,and FSPE methods.The proposed method showed remarkable linearity(r=0.9998;range:0.0840-48.0 mg/g),low limit of quantification(0.0840 mg/g),and high precision(relative standard deviation<5.6%).Therefore,the PDES-GO-UADFE-HPLC method shows significant potential in the field of pharmaceutical analysis for the separation and analysis of anti-cancer compounds in complex plant samples.
基金supported by the National Key R&D Program of China(2016YFC0204300)the National Natural Science Foundation of China(21477109)~~
文摘A series of(Ce,Cr)xO2/Nb2O5 catalysts with different(Ce,Cr)xO2 to Nb2O5 mass ratios were synthesized by the deposition-precipitation method for use in deep catalytic oxidation of 1,2-dichloroethane(DCE), which is one of the typical chlorinated volatile organic compound pollutants. The textural properties were characterized by X-ray diffraction, N2 adsorption/desorption isotherms, UV-Raman spectroscopy, and scanning electron microscopy. The surface acidity and the redox properties were characterized by ammonia temperature-programmed desorption and H2 temperature-programmed reduction, respectively. The results show that the addition of a proper amount of(Ce,Cr)xO2 over Nb2O5 significantly improves the intrinsic catalytic activity towards the deep oxidation of DCE, and only a very small amount of C2H3Cl is detected as the byproduct of the oxidation process. Further study reveals the existence of an obvious synergistic effect between Nb2O5, with abundant strong acid sites, and(Ce,Cr)xO2, with strong oxidation sites, as the strong acid sites of Nb2O5 promote the adsorption and dehydrochlorination of DCE, while the strong oxidation sites of(Ce,Cr)xO2 contribute to the deep oxidation of the reactant, intermediates, and byproducts.
