Engineering the morphology of the support is effective in tuning the redox properties of active metals for efficient catalytic methane combustion via tailoring the metal-support interaction.Herein,uniform Ir nanoparti...Engineering the morphology of the support is effective in tuning the redox properties of active metals for efficient catalytic methane combustion via tailoring the metal-support interaction.Herein,uniform Ir nanoparticles supported on anatase TiO_(2)with different morphologies predominantly exposing{100},{101},and{001}planes were synthesized and tested for methane combustion.The CH_(4) catalytic activity shows a remarkable TiO_(2)-facet-dependent effect and follows the order of Ir/TiO_(2)-{100}>Ir/TiO_(2)-{101}>>Ir/TiO_(2)-{001}.Detailed characterizations and DFT calculations reveal that compared with Ir-TiO_(2)-{101}and Ir-TiO_(2)-{001}interfaces,the superior Ir-TiO_(2)-{100}interface facilitates the generation of electron-rich Ir species through more profound charge transfer from TiO_(2)-{100}to Ir atoms.The electron-rich Ir structure,featuring abundant defect oxygen vacancies,significantly enhances the redox properties of active Ir species and reduces the activation energy for breaking the initial C-H bond in CH_(4),resulting in the superior catalytic activity for methane combustion.These findings deepen fundamental insights into the TiO_(2)-facet-dependent reactivity of different Ir/TiO_(2)nanomaterials in methane oxidation and pave the way for designing efficient Ir-based methane oxidation catalysts.展开更多
Pt-HSiW/CeO_(2) catalysts were prepared for chlorobenzene(CB) catalytic combustion by hydrothermal method at different calcination temperatures,and the effects of the surface acidity and chemical valence on the cataly...Pt-HSiW/CeO_(2) catalysts were prepared for chlorobenzene(CB) catalytic combustion by hydrothermal method at different calcination temperatures,and the effects of the surface acidity and chemical valence on the catalytic activity were investigated.The results show that the catalyst calcined at 450℃(Cat-B)exhibits the outstanding catalytic performance,and the Cat-B catalyst possesses 90% conversion of CB at148℃.The excellent catalytic activity of Cat-B is attributed to more Ce^(3+)/(Ce^(3+)+Ce^(4+)),Pt~0/(Pt^(0)+Pt^(2+)),O_(ads)/(O_(latt)+O_(ads)) and Lewis acid sites.The degradation mechanism is proposed based on the analysis of the intermediates with the following reaction pathway:chlorobenzene→phenates/benzoquinone→acetate→maleate→CO_(2)+H_(2)O.展开更多
The pressurized combustion experiments of bituminous coal and lignite under air and O2/CO2 atmospheres were conducted to study the influences of pressure and atmosphere on combustion and the CO, NO, SO2 release proces...The pressurized combustion experiments of bituminous coal and lignite under air and O2/CO2 atmospheres were conducted to study the influences of pressure and atmosphere on combustion and the CO, NO, SO2 release process. Two indices, the maximum concentration and the total emission, were applied to quantitatively evaluate the influence of several different operating parameters such as pressure, atmosphere and temperature on the formation of NO and SO2 during coal combustion in the fluidized bed. The experimental results show that the releasing profiles of CO, NO and SO2 during coal combustion under a pressurized oxy- fuel atmosphere are similar to those under a pressurized air atmosphere, and the curves of measured gas components are all unimodal. Under the oxy-fuel condition, pressure increasing from 0.1 to 0.7 MPa can cause the inhibition of NO and SO2 emission. The elevation of temperature can lead to an increase in the maximum concentration and the total production of NO and SO2, and the increase under atmospheric pressure is higher than that under high pressure.展开更多
In order to analyze the influence of the addition of yttrium and manganese on the soot combustion performance and high temperature stability of CeO_(2) catalyst,a series of Y/Mn-modified CeO_(2) catalysts were prepare...In order to analyze the influence of the addition of yttrium and manganese on the soot combustion performance and high temperature stability of CeO_(2) catalyst,a series of Y/Mn-modified CeO_(2) catalysts were prepared.The effects of structural properties,textural properties,oxygen vacancies,Ce^(3+),surface adsorbed oxygen species,reduction properties and desorption properties of oxygen species on the activity were analyzed by various characterization methods.The results of the activity test show that the addition of manganese is beneficial to enhancement of the activity,while the addition of yttrium increases the amount of reactive oxygen species,but decreases the activity.After aging at 700℃,the activity of the CeMn catalyst decreases most sharply,while the catalytic activity of the CeY catalyst can be maintained to a certain extent.Interestingly,the addition of yttrium and manganese at the same time can stabilize the activity.The fundamental reason is that yttrium and manganese move to the surface of the solid solution after aging,which increases the reduction performance of the catalyst,thus contributing to the increase of activity.Although the activity of CeYMn catalyst decreases after aging at 800℃,it is still higher than that of other catalysts aged at 700℃.展开更多
We have realized efficient photopatterning and high-quality ZrO_(2)films through combustion synthesis and manufactured resistive random access memory(RRAM)devices with excellent switching stability at low temperatures...We have realized efficient photopatterning and high-quality ZrO_(2)films through combustion synthesis and manufactured resistive random access memory(RRAM)devices with excellent switching stability at low temperatures(250℃)using these approaches.Combustion synthesis reduces the energy required for oxide conversion,thus accelerating the decomposition of organic ligands in the UV-exposed area,and promoting the formation of metal-oxygen networks,contributing to patterning.Thermal analysis confirmed a reduction in the conversion temperature of combustion precursors,and the prepared combustion ZrO_(2)films exhibited a high proportion of metal-oxygen bonding that constitutes the oxide lattice,along with an amorphous phase.Furthermore,the synergistic effect of combustion synthesis and UV/O_(3)-assisted photochemical activation resulted in patterned ZrO_(2)films forming even more complete metal-oxygen networks.RRAM devices fabricated with patterned ZrO_(2)films using combustion synthesis exhibited excellent switching characteristics,including a narrow resistance distribution,endurance of 103 cycles,and retention for 105 s at 85℃,despite low-temperature annealing.Combustion synthesis not only enables the formation of high-quality metal oxide films with low external energy but also facilitates improved photopatterning.展开更多
文摘Engineering the morphology of the support is effective in tuning the redox properties of active metals for efficient catalytic methane combustion via tailoring the metal-support interaction.Herein,uniform Ir nanoparticles supported on anatase TiO_(2)with different morphologies predominantly exposing{100},{101},and{001}planes were synthesized and tested for methane combustion.The CH_(4) catalytic activity shows a remarkable TiO_(2)-facet-dependent effect and follows the order of Ir/TiO_(2)-{100}>Ir/TiO_(2)-{101}>>Ir/TiO_(2)-{001}.Detailed characterizations and DFT calculations reveal that compared with Ir-TiO_(2)-{101}and Ir-TiO_(2)-{001}interfaces,the superior Ir-TiO_(2)-{100}interface facilitates the generation of electron-rich Ir species through more profound charge transfer from TiO_(2)-{100}to Ir atoms.The electron-rich Ir structure,featuring abundant defect oxygen vacancies,significantly enhances the redox properties of active Ir species and reduces the activation energy for breaking the initial C-H bond in CH_(4),resulting in the superior catalytic activity for methane combustion.These findings deepen fundamental insights into the TiO_(2)-facet-dependent reactivity of different Ir/TiO_(2)nanomaterials in methane oxidation and pave the way for designing efficient Ir-based methane oxidation catalysts.
基金Project supported by the National Natural Science Foundation of China (21872096)Key Research and Development Project of Henan Province (231111320400)+3 种基金Zhongyuan Yingcai Jihua (ZYYCYU202012183)Academic Leader of Henan Institute of Urban Construction (YCJXSJSDTR202204)College Students'Innovation and Entrepreneurship Training Program of Henan Province(202211765053)Doctoral Research Start-up Project of Henan University of Urban Construction (990/Q2017011)。
文摘Pt-HSiW/CeO_(2) catalysts were prepared for chlorobenzene(CB) catalytic combustion by hydrothermal method at different calcination temperatures,and the effects of the surface acidity and chemical valence on the catalytic activity were investigated.The results show that the catalyst calcined at 450℃(Cat-B)exhibits the outstanding catalytic performance,and the Cat-B catalyst possesses 90% conversion of CB at148℃.The excellent catalytic activity of Cat-B is attributed to more Ce^(3+)/(Ce^(3+)+Ce^(4+)),Pt~0/(Pt^(0)+Pt^(2+)),O_(ads)/(O_(latt)+O_(ads)) and Lewis acid sites.The degradation mechanism is proposed based on the analysis of the intermediates with the following reaction pathway:chlorobenzene→phenates/benzoquinone→acetate→maleate→CO_(2)+H_(2)O.
基金The National Natural Science Foundation of China(No.51206023)the National Key Basic Research Program of China(973 Program)(No.2011CB707301-3)the Fundamental Research Funds for the Central Universities
文摘The pressurized combustion experiments of bituminous coal and lignite under air and O2/CO2 atmospheres were conducted to study the influences of pressure and atmosphere on combustion and the CO, NO, SO2 release process. Two indices, the maximum concentration and the total emission, were applied to quantitatively evaluate the influence of several different operating parameters such as pressure, atmosphere and temperature on the formation of NO and SO2 during coal combustion in the fluidized bed. The experimental results show that the releasing profiles of CO, NO and SO2 during coal combustion under a pressurized oxy- fuel atmosphere are similar to those under a pressurized air atmosphere, and the curves of measured gas components are all unimodal. Under the oxy-fuel condition, pressure increasing from 0.1 to 0.7 MPa can cause the inhibition of NO and SO2 emission. The elevation of temperature can lead to an increase in the maximum concentration and the total production of NO and SO2, and the increase under atmospheric pressure is higher than that under high pressure.
基金Project supported by the National Natural Science Foundation of China(21962021)the Yunnan Fundamental Research Projects(202001AU070121)+1 种基金the National Natural Science Foundation of China(51908091)the Special Basic Cooperative Research Programs of Yunnan Provincial Undergraduate Universities'Association(202101BA070001-084)。
文摘In order to analyze the influence of the addition of yttrium and manganese on the soot combustion performance and high temperature stability of CeO_(2) catalyst,a series of Y/Mn-modified CeO_(2) catalysts were prepared.The effects of structural properties,textural properties,oxygen vacancies,Ce^(3+),surface adsorbed oxygen species,reduction properties and desorption properties of oxygen species on the activity were analyzed by various characterization methods.The results of the activity test show that the addition of manganese is beneficial to enhancement of the activity,while the addition of yttrium increases the amount of reactive oxygen species,but decreases the activity.After aging at 700℃,the activity of the CeMn catalyst decreases most sharply,while the catalytic activity of the CeY catalyst can be maintained to a certain extent.Interestingly,the addition of yttrium and manganese at the same time can stabilize the activity.The fundamental reason is that yttrium and manganese move to the surface of the solid solution after aging,which increases the reduction performance of the catalyst,thus contributing to the increase of activity.Although the activity of CeYMn catalyst decreases after aging at 800℃,it is still higher than that of other catalysts aged at 700℃.
基金supported by the National Research Founda-tion of Korea(NRF)grants funded by the Ministry of Science and ICT(MSIT)(Nos.RS-2023-00251283,RS-2023-00257003,and 2022M3D1A2083618)supported by the DGIST R&D Program of the MSIT(No.23-CoE-BT-03).
文摘We have realized efficient photopatterning and high-quality ZrO_(2)films through combustion synthesis and manufactured resistive random access memory(RRAM)devices with excellent switching stability at low temperatures(250℃)using these approaches.Combustion synthesis reduces the energy required for oxide conversion,thus accelerating the decomposition of organic ligands in the UV-exposed area,and promoting the formation of metal-oxygen networks,contributing to patterning.Thermal analysis confirmed a reduction in the conversion temperature of combustion precursors,and the prepared combustion ZrO_(2)films exhibited a high proportion of metal-oxygen bonding that constitutes the oxide lattice,along with an amorphous phase.Furthermore,the synergistic effect of combustion synthesis and UV/O_(3)-assisted photochemical activation resulted in patterned ZrO_(2)films forming even more complete metal-oxygen networks.RRAM devices fabricated with patterned ZrO_(2)films using combustion synthesis exhibited excellent switching characteristics,including a narrow resistance distribution,endurance of 103 cycles,and retention for 105 s at 85℃,despite low-temperature annealing.Combustion synthesis not only enables the formation of high-quality metal oxide films with low external energy but also facilitates improved photopatterning.
