The performance of catalysts used in after-treatment systems is the key factor for the removal of diesel soot,which is an important component of atmosphericfine particle emissions.Herein,three-dimensionally ordered ma...The performance of catalysts used in after-treatment systems is the key factor for the removal of diesel soot,which is an important component of atmosphericfine particle emissions.Herein,three-dimensionally ordered macroporous–mesoporous Ti_(x)Si+(1-x)O_(2)(3DOM-m Ti_(x)Si+(1-x)O_(2)) and its supported MnO_(x)catalysts doped with different alkali/alkaline-earth metals (AMnO_(x)/3 DOM-m Ti_(0.7)Si_(0.3)O_(2)(A:Li,Na,K,Ru,Cs,Mg,Ca,Sr,Ba)) were prepared by mesoporous template (P123)-assisted colloidal crystal template (CCT) and incipient wetness impregnation methods,respectively.Physicochemical characterizations of the catalysts were performed using scanning electron microscopy,X-ray diffraction,N_(2)adsorption–desorption,H_(2)temperature-programmed reduction,O_(2)temperature-programmed desorption,NO temperature-programmed oxidation,and Raman spectroscopy techniques;then,we evaluated their catalytic performances for the removal of diesel soot particles.The results show that the 3DOM-m Ti_(0.7)Si_(0.3)O_(2)supports exhibited a well-defined 3DOM-m nanostructure,and AMnO_(x)nanoparticles with 10–50 nm were evenly dispersed on the inner walls of the uniform macropores.In addition,the as-prepared catalysts exhibited good catalytic performance for soot combustion.Among the prepared catalysts,CsMnO_(x)/3DOM-m Ti_(0.7)Si_(0.3)O_(2)had the highest catalytic activity for soot combustion,with T10,T50,and T90(the temperatures corresponding to soot conversion rates of 10%,50%,and 90%) values of 285,355,and 393℃,respectively.The high catalytic activity of the CsMnO_(x)/3 DOM-m Ti_(0.7)Si_(0.3)O_(2)catalysts was attributed to their excellent low-temperature reducibility and homogeneous macroporous–mesoporous structure,as well as to the synergistic effects between Cs and Mn species and between CsMnO_(x)and the Ti_(0.7)Si_(0.3)O_(2)support.展开更多
Wide bandgap semiconductors are crucially significant for optoelectronic and thermoelectric device applications.Metal nitride is a class of semiconductor material with great potential.Under high pressure,the bandgap o...Wide bandgap semiconductors are crucially significant for optoelectronic and thermoelectric device applications.Metal nitride is a class of semiconductor material with great potential.Under high pressure,the bandgap of magnesium nitride was predicted to grow.Raman spectra,ultra-violet-visible(UV-Vis)absorption spectra,and first-principles calculations were employed in this study to analyze the bandgap evolution of Mg_(3)N_(2).The widening of the bandgap has been first detected experimentally,with the gap increasing from 2.05 eV at 3 GPa to 2.88 eV at 47 GPa.According to the calculation results,the enhanced covalent component is responsible for the bandgap widening.展开更多
Anew mixed alkali and alkaline-earth metal borate Na4Ca2[B14O22(OH)6]·2H2O(1) has been made under a mild solvothermal condition and characterized by single-crystal X-ray diffraction, infrared(IR) spectroscopy, UV...Anew mixed alkali and alkaline-earth metal borate Na4Ca2[B14O22(OH)6]·2H2O(1) has been made under a mild solvothermal condition and characterized by single-crystal X-ray diffraction, infrared(IR) spectroscopy, UV-Vis diffuse reflectance spectroscopy, powder X-ray diffraction and thermogravimetric analysis, respectively. Compound 1 features a 1D tube based on[B14O24(OH)6]12-({B14}-1) oxo-boron clusters. Such a tube built by {B14}-1 units has been discovered for the first time in borate system. These tubes are arranged orderly to generate 2D layers and a further 3D supramolecular network through hydrogen bond interactions. UV-Vis diffuse reflectance spectrum reveals that compound 1 is a wide band-gap semiconductor and has potential application in UV region.展开更多
基金supported by Key Research and Development Program of Ministry of Science and Technology of the People’s Republic of China (MOST) (No. 2017YFE0131200) for collaboration between China and PolandNational Nature Science Foundation of China (NSFC) (Nos. 22072095, U1908204, 21761162016)+3 种基金General Projects of Liaoning Province Natural Fund (No. 2019-MS-284)National Engineering Laboratory for Mobile Source Emission Control Technology (No. NELMS2018A04)University level innovation team of Shenyang Normal University, Major Incubation Program of Shenyang Normal University (No. ZD201901)supported by the Research Grants Council (RGC) of Hong Kong through NSFC/RGC Joint Research Scheme (No. N_CUHK451/17)。
文摘The performance of catalysts used in after-treatment systems is the key factor for the removal of diesel soot,which is an important component of atmosphericfine particle emissions.Herein,three-dimensionally ordered macroporous–mesoporous Ti_(x)Si+(1-x)O_(2)(3DOM-m Ti_(x)Si+(1-x)O_(2)) and its supported MnO_(x)catalysts doped with different alkali/alkaline-earth metals (AMnO_(x)/3 DOM-m Ti_(0.7)Si_(0.3)O_(2)(A:Li,Na,K,Ru,Cs,Mg,Ca,Sr,Ba)) were prepared by mesoporous template (P123)-assisted colloidal crystal template (CCT) and incipient wetness impregnation methods,respectively.Physicochemical characterizations of the catalysts were performed using scanning electron microscopy,X-ray diffraction,N_(2)adsorption–desorption,H_(2)temperature-programmed reduction,O_(2)temperature-programmed desorption,NO temperature-programmed oxidation,and Raman spectroscopy techniques;then,we evaluated their catalytic performances for the removal of diesel soot particles.The results show that the 3DOM-m Ti_(0.7)Si_(0.3)O_(2)supports exhibited a well-defined 3DOM-m nanostructure,and AMnO_(x)nanoparticles with 10–50 nm were evenly dispersed on the inner walls of the uniform macropores.In addition,the as-prepared catalysts exhibited good catalytic performance for soot combustion.Among the prepared catalysts,CsMnO_(x)/3DOM-m Ti_(0.7)Si_(0.3)O_(2)had the highest catalytic activity for soot combustion,with T10,T50,and T90(the temperatures corresponding to soot conversion rates of 10%,50%,and 90%) values of 285,355,and 393℃,respectively.The high catalytic activity of the CsMnO_(x)/3 DOM-m Ti_(0.7)Si_(0.3)O_(2)catalysts was attributed to their excellent low-temperature reducibility and homogeneous macroporous–mesoporous structure,as well as to the synergistic effects between Cs and Mn species and between CsMnO_(x)and the Ti_(0.7)Si_(0.3)O_(2)support.
基金supported by the Open Project of State Key Laboratory of Superhard Materials,Jilin University(Grant No.202102)Young Science Foundation of Northeast Petroleum University(Grant No.2018QNL-53)。
文摘Wide bandgap semiconductors are crucially significant for optoelectronic and thermoelectric device applications.Metal nitride is a class of semiconductor material with great potential.Under high pressure,the bandgap of magnesium nitride was predicted to grow.Raman spectra,ultra-violet-visible(UV-Vis)absorption spectra,and first-principles calculations were employed in this study to analyze the bandgap evolution of Mg_(3)N_(2).The widening of the bandgap has been first detected experimentally,with the gap increasing from 2.05 eV at 3 GPa to 2.88 eV at 47 GPa.According to the calculation results,the enhanced covalent component is responsible for the bandgap widening.
基金This work was supported by the National Natural Science Foundation of China (Nos.21571016,21831001,91122028)the National Natural Science Foundation of China for Distinguished Young Scholars(No.20725101).
文摘Anew mixed alkali and alkaline-earth metal borate Na4Ca2[B14O22(OH)6]·2H2O(1) has been made under a mild solvothermal condition and characterized by single-crystal X-ray diffraction, infrared(IR) spectroscopy, UV-Vis diffuse reflectance spectroscopy, powder X-ray diffraction and thermogravimetric analysis, respectively. Compound 1 features a 1D tube based on[B14O24(OH)6]12-({B14}-1) oxo-boron clusters. Such a tube built by {B14}-1 units has been discovered for the first time in borate system. These tubes are arranged orderly to generate 2D layers and a further 3D supramolecular network through hydrogen bond interactions. UV-Vis diffuse reflectance spectrum reveals that compound 1 is a wide band-gap semiconductor and has potential application in UV region.
