A series of carbon nitride(CN)materials represented by graphitic carbon nitride(g-C_(3)N_(4))have been widely used in bioimaging,biosensing,and other fields in recent years due to their nontoxicity,low cost,and high l...A series of carbon nitride(CN)materials represented by graphitic carbon nitride(g-C_(3)N_(4))have been widely used in bioimaging,biosensing,and other fields in recent years due to their nontoxicity,low cost,and high luminescent quantum efficiency.What is more attractive is that the luminescent properties such as wavelength and intensity can be regulated by controlling the structure at the molecular level.Hence,it is time to summarize the related research on CN structural evolution and make a prospect on future developments.In this review,we first summarize the research history and multiple structural evolution of CN.Then,the progress of improving the luminescence performance of CN through structural evolution was discussed.Significantly,the relationship between CN structure evolution and energy conversion in the forms of photoluminescence,chemiluminescence,and electrochemiluminescence was reviewed.Finally,key challenges and opportunities such as nanoscale dispersion strategy,luminous efficiency improving methods,standardization evaluation,and macroscopic preparation of CN are highlighted.展开更多
Recent experimental advancements reported a chemical reaction between antimony and nitrogen under high temperature and high pressure,yielding crystalline antimony nitride(Sb_(3)N_(5))with an orthorhombic structure.Mot...Recent experimental advancements reported a chemical reaction between antimony and nitrogen under high temperature and high pressure,yielding crystalline antimony nitride(Sb_(3)N_(5))with an orthorhombic structure.Motivated by this statement,we calculate the stability,elastic properties,electronic properties and energy density of the Cmc2_(1) structure for pnictogen nitrides X_(3)N_(5)(X=P,As,Sb,and Bi)using first-principles calculations combined with particle swarm optimization algorithms.Calculations of formation enthalpies,elastic constants and phonon spectra show that P_(3)N_(5),As_(3)N_(5) and Sb_(3)N_(5) are thermodynamically,mechanically and kinetically stable at 35 GPa,whereas Bi_(3)N_(5) is mechanically and kinetically stable but thermodynamically unstable.The computed electronic density of states shows strong covalent bonding between the N atoms and the phosphorus group atoms in the four compounds,confirmed by the calculated electronic localization function.We also calculate the energy densities for Sb_(3)N_(5) and find it to be a potentially high-energy-density material.展开更多
Multi-phase nitrides bonded silicon carbide lintel blocks were prepared using industrial SiC(SiC≥98 mass%,3-0.5,≤0.5 and≤0.044 mm),Si powder(Si≥98 mass%,≤0.044 mm),and SiO2 micropowder(SiO2≥96 mass%,d50=0.15 pm)...Multi-phase nitrides bonded silicon carbide lintel blocks were prepared using industrial SiC(SiC≥98 mass%,3-0.5,≤0.5 and≤0.044 mm),Si powder(Si≥98 mass%,≤0.044 mm),and SiO2 micropowder(SiO2≥96 mass%,d50=0.15 pm)as raw materials,and calcium lignosulfonate as the additive,batching,mixing,and molding on a vibration pressure molding machine,drying and then firing at 1420℃for 10 h in high-purity N2.The apparent porosity,the bulk density,the cold modulus of rupture,the hot modulus of rupture,and the linear expansion coefficient of the samples were tested.The phase composition and the microstructure of the samples at different nitriding depths(50,100,and 150 mm)were analyzed by XRD and SEM.The field application effects of the blocks were studied.The results show that:(1)the multi-phase nitrides bonded silicon carbide refractories can dynamically adjust their own phase composition and minimize structural and thermal stresses,improving the service life of key parts of dry quenching furnaces;(2)calcium lignosulfonate can improve the nitriding micro-environment of multi-phase nitrides bonded silicon carbide lintel blocks,successfully increasing the effective nitriding thickness of the blocks to 300 mm;(3)Sinosteel LI RR provides a unique concept in the design of materials and block types as well as the stable and scientific overall structure,promoting the industrialization process of dry quenching furnaces with long service life in China.展开更多
为加速二苯醚类除草剂在可见光环境的降解,以玉米芯制碳量子点修饰石墨相氮化碳,合成一种非金属型光催化剂.考察在该催化剂作用下,氟磺胺草醚、三氟羧草醚和乙氧氟草醚等的光解行为及光解前后毒性.结果表明,氟磺胺草醚在可见光照射下的...为加速二苯醚类除草剂在可见光环境的降解,以玉米芯制碳量子点修饰石墨相氮化碳,合成一种非金属型光催化剂.考察在该催化剂作用下,氟磺胺草醚、三氟羧草醚和乙氧氟草醚等的光解行为及光解前后毒性.结果表明,氟磺胺草醚在可见光照射下的光解速率最大、其次为乙氧氟草醚,光照3 h的降解率即达99%和91%,而三氟羧草醚的光解速率最低、须光照至8 h才能达到90%的降解率.由高斯软件计算NPA(Natural Population Analysis)电荷分布得福井函数和双描述符,预测反应位点并结合液质联用分析降解产物,推测除草剂的降解过程应包括裂解、水解、脱卤、还原和羟基化等,证明了空穴和羟基自由基在其中的作用.观察玉米种子的生长实验,发现氟磺胺草醚的毒性略高于乙氧氟草醚,但二者经光照处理后毒性均显著下降,三氟羧草醚及其光解产物显示为低毒性.展开更多
基金Natural Science Foundation of Hebei ProvinceTangshan Talent Funding Project,Grant/Award Number:E2022209039+1 种基金Key Research Project of North China University of Science and Technology,Grant/Award Number:ZD-YG 202301Tangshan Talent Punding Project,Grant/Award Number:A202202007
文摘A series of carbon nitride(CN)materials represented by graphitic carbon nitride(g-C_(3)N_(4))have been widely used in bioimaging,biosensing,and other fields in recent years due to their nontoxicity,low cost,and high luminescent quantum efficiency.What is more attractive is that the luminescent properties such as wavelength and intensity can be regulated by controlling the structure at the molecular level.Hence,it is time to summarize the related research on CN structural evolution and make a prospect on future developments.In this review,we first summarize the research history and multiple structural evolution of CN.Then,the progress of improving the luminescence performance of CN through structural evolution was discussed.Significantly,the relationship between CN structure evolution and energy conversion in the forms of photoluminescence,chemiluminescence,and electrochemiluminescence was reviewed.Finally,key challenges and opportunities such as nanoscale dispersion strategy,luminous efficiency improving methods,standardization evaluation,and macroscopic preparation of CN are highlighted.
基金the Young Talent Project of the Scientific Research Plan by the Hubei Provincial Department of Education(Grant No.Q20234301)the Guiding Project of the Scientific Research Plan by the Hubei Provincial Department of Education(Grant No.B2023222)+2 种基金the Natural Science Foundation of Hubei Province(Grant No.2022CFB527)the Scientific Research Project of Jingchu University of Technology(Grant Nos.YY202401,096201-5 Chin.Phys.B 33,096201(2024)YY202409,YY202207,and YB202212)the Open Research Projects of Jingchu University of Technology(Grant No.HX20240009).
文摘Recent experimental advancements reported a chemical reaction between antimony and nitrogen under high temperature and high pressure,yielding crystalline antimony nitride(Sb_(3)N_(5))with an orthorhombic structure.Motivated by this statement,we calculate the stability,elastic properties,electronic properties and energy density of the Cmc2_(1) structure for pnictogen nitrides X_(3)N_(5)(X=P,As,Sb,and Bi)using first-principles calculations combined with particle swarm optimization algorithms.Calculations of formation enthalpies,elastic constants and phonon spectra show that P_(3)N_(5),As_(3)N_(5) and Sb_(3)N_(5) are thermodynamically,mechanically and kinetically stable at 35 GPa,whereas Bi_(3)N_(5) is mechanically and kinetically stable but thermodynamically unstable.The computed electronic density of states shows strong covalent bonding between the N atoms and the phosphorus group atoms in the four compounds,confirmed by the calculated electronic localization function.We also calculate the energy densities for Sb_(3)N_(5) and find it to be a potentially high-energy-density material.
文摘Multi-phase nitrides bonded silicon carbide lintel blocks were prepared using industrial SiC(SiC≥98 mass%,3-0.5,≤0.5 and≤0.044 mm),Si powder(Si≥98 mass%,≤0.044 mm),and SiO2 micropowder(SiO2≥96 mass%,d50=0.15 pm)as raw materials,and calcium lignosulfonate as the additive,batching,mixing,and molding on a vibration pressure molding machine,drying and then firing at 1420℃for 10 h in high-purity N2.The apparent porosity,the bulk density,the cold modulus of rupture,the hot modulus of rupture,and the linear expansion coefficient of the samples were tested.The phase composition and the microstructure of the samples at different nitriding depths(50,100,and 150 mm)were analyzed by XRD and SEM.The field application effects of the blocks were studied.The results show that:(1)the multi-phase nitrides bonded silicon carbide refractories can dynamically adjust their own phase composition and minimize structural and thermal stresses,improving the service life of key parts of dry quenching furnaces;(2)calcium lignosulfonate can improve the nitriding micro-environment of multi-phase nitrides bonded silicon carbide lintel blocks,successfully increasing the effective nitriding thickness of the blocks to 300 mm;(3)Sinosteel LI RR provides a unique concept in the design of materials and block types as well as the stable and scientific overall structure,promoting the industrialization process of dry quenching furnaces with long service life in China.
文摘为加速二苯醚类除草剂在可见光环境的降解,以玉米芯制碳量子点修饰石墨相氮化碳,合成一种非金属型光催化剂.考察在该催化剂作用下,氟磺胺草醚、三氟羧草醚和乙氧氟草醚等的光解行为及光解前后毒性.结果表明,氟磺胺草醚在可见光照射下的光解速率最大、其次为乙氧氟草醚,光照3 h的降解率即达99%和91%,而三氟羧草醚的光解速率最低、须光照至8 h才能达到90%的降解率.由高斯软件计算NPA(Natural Population Analysis)电荷分布得福井函数和双描述符,预测反应位点并结合液质联用分析降解产物,推测除草剂的降解过程应包括裂解、水解、脱卤、还原和羟基化等,证明了空穴和羟基自由基在其中的作用.观察玉米种子的生长实验,发现氟磺胺草醚的毒性略高于乙氧氟草醚,但二者经光照处理后毒性均显著下降,三氟羧草醚及其光解产物显示为低毒性.
