As alkali additive,KC1 catalyzes effectively the carbothermic reduction of pre-oxidized ilmenite,and the catalytic effect becomes more remarkable as the amount of KC1 increases.During the carbothermic reduction,the ga...As alkali additive,KC1 catalyzes effectively the carbothermic reduction of pre-oxidized ilmenite,and the catalytic effect becomes more remarkable as the amount of KC1 increases.During the carbothermic reduction,the gaseous product consists mainly of CO,and the partial pressure of which increases with reaction temperature.The EPMA and XPS of the partially reduced ilmenite ore and that of the used graphite as reductant showed that the potassium ions enter both ilmenite particles and graphite powders during reduction.The above-mentioned phenomena result in the distortion of ilmenite and carbon structure by potassium ions and reaction activity of carbon and ilmenite was enhanced.As a result,the overall carbothermic reduction was catalyzed by KC1.展开更多
As a white pigment, titanium oxide is used for cosmetic application. This oxide is well known to have the photo catalytic activity. Therefore a certain degree of sebum is decomposed by the ultraviolet radiation in sun...As a white pigment, titanium oxide is used for cosmetic application. This oxide is well known to have the photo catalytic activity. Therefore a certain degree of sebum is decomposed by the ultraviolet radiation in sunlight. In this work, titanium phosphates were prepared with additives (urea, sodium lactate, and glycerin) as a novel white pigment. Their chemical composition, powder properties, photo catalytic activity, moisture retention, and smoothness were studied. These white pigments had little photo catalytic activity. The addition of sodium lactate and glycerin improved the moisture retention of titanium phosphates. The slipping resistance of samples became small by the addition of sodium lactate and glycerin. The roughness of samples became small by heating.展开更多
The FCC unit with addition of various inventories of the FP-DSN type sulfur transfer additive was tested in a commercial scale. The effect of the sulfur transfer additive was analyzed by investigating the indicators r...The FCC unit with addition of various inventories of the FP-DSN type sulfur transfer additive was tested in a commercial scale. The effect of the sulfur transfer additive was analyzed by investigating the indicators related with the regenerator flue gas composition,the dry gas composition before desulfurization,the LPG composition before desulfurization,the acid gas,and the yield of gasoline and diesel. The test results indicated that the sulfur was trans ferred from the feed stream into the dry gas,LPG and acid gas,and the sulfur transfer effect was obvious only when the inventory of sulfur transfer additive exceeded over 2.0% of total FCC catalyst inventory.展开更多
The paper presents the results of investigation of changes in the composition of hydrocarbons and sulfur-containing compounds of an atmospheric residue in the course of cracking in the presence of a tungsten carbide-n...The paper presents the results of investigation of changes in the composition of hydrocarbons and sulfur-containing compounds of an atmospheric residue in the course of cracking in the presence of a tungsten carbide-nickel-chromium(WC/Ni-Cr)catalytic additive and without it.The cracking is carried out in an autoclave at 500℃for 30 min.The addition of the WC/Ni-Cr additive promotes the deepening of reactions of destruction not only of resins and asphaltenes,but also high molecular weight naphthene-aromatic compounds of the atmospheric residue.It is shown that the content of low molecular weight C9-C17 n-alkanes and C9-C10 alkylbenzenes rose sharply in the products of cracking with addition of WC/Ni-Cr in comparison with those produced without the additive.Alkyl-and naphthene-substituted aromatic hydrocarbons of benzene,naphthalene,phenanthrene series,polyarenes,benzo-and dibenzothiophenes are identified.展开更多
The iodine-catalyzed nucleophilic addition of pyrrole to acetone has been studied by density functional theory at the level of Lanl2DZ＊. It has been shown that the first iodine molecule appears to have a remarkable c...The iodine-catalyzed nucleophilic addition of pyrrole to acetone has been studied by density functional theory at the level of Lanl2DZ＊. It has been shown that the first iodine molecule appears to have a remarkable catalytic effect on this reaction by halogen bond between carbonyl oxygen and iodine molecule, but the second one does not improve the reaction largely. In general, the nucleophilic addition at the C（2） site of pyrrole is more favorable than that at the C（3） site; however, this trend is not prominent or even changed in acetronitrile solvent for the indole system, which is consistent with the experimental result by Bandgar.展开更多
The iodine-catalyzed nucleophilic addition reactions of pyrrole, furan, or thiophene with acetone were studied in gas and solvent by the density functional theory at the level of Lanl2DZ^＊. It was seen that the halog...The iodine-catalyzed nucleophilic addition reactions of pyrrole, furan, or thiophene with acetone were studied in gas and solvent by the density functional theory at the level of Lanl2DZ^＊. It was seen that the halogen bond between iodine and carbonyl oxygen appeared to have an important catalytic effect on such reactions, and the first iodine molecule maximally diminished the barrier height by 41 kJ/mol, while the second iodine molecule could not improve such reactions largely. It was concluded that the C2-addition was generally more favorable than the C3-addition for the three heterocycles; however, iodine considerably more effectively catalyzed the C3-addition than the C2-addition for pyrrole. It was also revealed by PCM calculation that the iodine-catalyzed nucleophilic additions occurred more easily in solvent than in gas, which explained the experiment performed by Bandgar et al..展开更多
CO_(2)hydrogenation has been considered to be a highly promising route for the production of high-value olefins(HVOs)while also mitigating CO_(2)emissions.However,it is challenging to achieve high selectivity and main...CO_(2)hydrogenation has been considered to be a highly promising route for the production of high-value olefins(HVOs)while also mitigating CO_(2)emissions.However,it is challenging to achieve high selectivity and maintain stable performance for HVOs(ethylene,propylene,and linear a-olefins)over a prolonged reaction time due to the difficulty in precise control of carbon coupling and rapid catalyst deactivation.Herein,we present a selective Ba and Na co-modified Fe catalyst enriched with Fe_(5)C_(2)and Fe_(3)C active sites that can boost HVO synthesis with up to 66.1%selectivity at an average CO_(2)conversion of 38%for over 500 h.Compared to traditional NaFe catalyst,the combined effect of Ba and Na additives in the NaBaFe-0.5 catalyst suppressed excess oxidation of FeCxsites by H_(2)O.The absence of Fe3O4phase in the spent NaBaFe-0.5 catalyst reflects the stabilization effect of the co-modifiers on the FeCxsites.This study provides a strategy to design Fe-based catalysts that can be scaled up for the stable synthesis of HVOs from CO_(2)hydrogenation.展开更多
The practical application of lithium–sulfur batteries(LSBs)is severely hindered by the undesirable shuttling of lithium polysulfides(LiPSs)and sluggish redox kinetics of sulfur species.Herein,a series of ultrathin si...The practical application of lithium–sulfur batteries(LSBs)is severely hindered by the undesirable shuttling of lithium polysulfides(LiPSs)and sluggish redox kinetics of sulfur species.Herein,a series of ultrathin singleatomic tungsten-doped Co_(3)O_(4)(Wx-Co_(3)O_(4))nanosheets as catalytic additives in the sulfur cathode for LSBs are rationally designed and synthesized.Benefiting from the enhanced catalytic activity and optimized electronic structure by W doping,the Wx-Co_(3)O_(4) not only reduces the shuttling of LiPSs but also decreases the energy barrier of sulfur redox reactions of sulfur species,leading to accelerated electrode kinetic.As a result,LSB cathodes with the use of 5.0 wt%W0.02-Co_(3)O_(4) as the electrocatalyst show the high reversible capacities of 1217.0 and 558.6 mAh g^(-1) at 0.2 and 5.0 C,respectively,and maintain a high reversible capacity of 644.6 mAh g^(-1) at 1.0 C(1.0 C=1675 mA g^(-1))after 500 cycles.With a high sulfur loading of 5.5 mg cm^(-2) and electrolyte–electrode ratio of 8μL_(electrolyte) mg_(sulfur)^(-1),the 5.0 wt%W_(0.02)-Co_(3)O_(4)-based sulfur cathode also retains a high reversible areal capacity of 3.86 mAh cm^(-2) at 0.1 C after 50 cycles with an initial capacity retention of 84.7%.展开更多
基金Item Sponsored by National Natural Science Foundation(59774026)
文摘As alkali additive,KC1 catalyzes effectively the carbothermic reduction of pre-oxidized ilmenite,and the catalytic effect becomes more remarkable as the amount of KC1 increases.During the carbothermic reduction,the gaseous product consists mainly of CO,and the partial pressure of which increases with reaction temperature.The EPMA and XPS of the partially reduced ilmenite ore and that of the used graphite as reductant showed that the potassium ions enter both ilmenite particles and graphite powders during reduction.The above-mentioned phenomena result in the distortion of ilmenite and carbon structure by potassium ions and reaction activity of carbon and ilmenite was enhanced.As a result,the overall carbothermic reduction was catalyzed by KC1.
文摘As a white pigment, titanium oxide is used for cosmetic application. This oxide is well known to have the photo catalytic activity. Therefore a certain degree of sebum is decomposed by the ultraviolet radiation in sunlight. In this work, titanium phosphates were prepared with additives (urea, sodium lactate, and glycerin) as a novel white pigment. Their chemical composition, powder properties, photo catalytic activity, moisture retention, and smoothness were studied. These white pigments had little photo catalytic activity. The addition of sodium lactate and glycerin improved the moisture retention of titanium phosphates. The slipping resistance of samples became small by the addition of sodium lactate and glycerin. The roughness of samples became small by heating.
文摘The FCC unit with addition of various inventories of the FP-DSN type sulfur transfer additive was tested in a commercial scale. The effect of the sulfur transfer additive was analyzed by investigating the indicators related with the regenerator flue gas composition,the dry gas composition before desulfurization,the LPG composition before desulfurization,the acid gas,and the yield of gasoline and diesel. The test results indicated that the sulfur was trans ferred from the feed stream into the dry gas,LPG and acid gas,and the sulfur transfer effect was obvious only when the inventory of sulfur transfer additive exceeded over 2.0% of total FCC catalyst inventory.
文摘The paper presents the results of investigation of changes in the composition of hydrocarbons and sulfur-containing compounds of an atmospheric residue in the course of cracking in the presence of a tungsten carbide-nickel-chromium(WC/Ni-Cr)catalytic additive and without it.The cracking is carried out in an autoclave at 500℃for 30 min.The addition of the WC/Ni-Cr additive promotes the deepening of reactions of destruction not only of resins and asphaltenes,but also high molecular weight naphthene-aromatic compounds of the atmospheric residue.It is shown that the content of low molecular weight C9-C17 n-alkanes and C9-C10 alkylbenzenes rose sharply in the products of cracking with addition of WC/Ni-Cr in comparison with those produced without the additive.Alkyl-and naphthene-substituted aromatic hydrocarbons of benzene,naphthalene,phenanthrene series,polyarenes,benzo-and dibenzothiophenes are identified.
基金the Natural Science Foundation of Zhejiang Province (Y406374)
文摘The iodine-catalyzed nucleophilic addition of pyrrole to acetone has been studied by density functional theory at the level of Lanl2DZ＊. It has been shown that the first iodine molecule appears to have a remarkable catalytic effect on this reaction by halogen bond between carbonyl oxygen and iodine molecule, but the second one does not improve the reaction largely. In general, the nucleophilic addition at the C（2） site of pyrrole is more favorable than that at the C（3） site; however, this trend is not prominent or even changed in acetronitrile solvent for the indole system, which is consistent with the experimental result by Bandgar.
基金the Natural Science Foundation of Zhejiang Province,China(No.Y406374)
文摘The iodine-catalyzed nucleophilic addition reactions of pyrrole, furan, or thiophene with acetone were studied in gas and solvent by the density functional theory at the level of Lanl2DZ^＊. It was seen that the halogen bond between iodine and carbonyl oxygen appeared to have an important catalytic effect on such reactions, and the first iodine molecule maximally diminished the barrier height by 41 kJ/mol, while the second iodine molecule could not improve such reactions largely. It was concluded that the C2-addition was generally more favorable than the C3-addition for the three heterocycles; however, iodine considerably more effectively catalyzed the C3-addition than the C2-addition for pyrrole. It was also revealed by PCM calculation that the iodine-catalyzed nucleophilic additions occurred more easily in solvent than in gas, which explained the experiment performed by Bandgar et al..
基金supported by the National Natural Science Foundation of China(21802138,21773234 and 22078315)the‘‘Transformational Technologies for Clean Energy and Demonstration’’,Strategic Priority Research Program of the Chinese Academy of Sciences(XDA 21090203)+3 种基金the Youth Innovation Promotion Association of Chinese Academy of Sciences(2020189)the Natural Science Foundation of Liaoning Province(2022-MS-027)the Youth Science and Technology Star Project Support Program of Dalian City(2021RQ123),DICP(Grant:DICP I202138)the University of Chinese Academy of Sciences(UCAS)for UCAS Scholarship。
文摘CO_(2)hydrogenation has been considered to be a highly promising route for the production of high-value olefins(HVOs)while also mitigating CO_(2)emissions.However,it is challenging to achieve high selectivity and maintain stable performance for HVOs(ethylene,propylene,and linear a-olefins)over a prolonged reaction time due to the difficulty in precise control of carbon coupling and rapid catalyst deactivation.Herein,we present a selective Ba and Na co-modified Fe catalyst enriched with Fe_(5)C_(2)and Fe_(3)C active sites that can boost HVO synthesis with up to 66.1%selectivity at an average CO_(2)conversion of 38%for over 500 h.Compared to traditional NaFe catalyst,the combined effect of Ba and Na additives in the NaBaFe-0.5 catalyst suppressed excess oxidation of FeCxsites by H_(2)O.The absence of Fe3O4phase in the spent NaBaFe-0.5 catalyst reflects the stabilization effect of the co-modifiers on the FeCxsites.This study provides a strategy to design Fe-based catalysts that can be scaled up for the stable synthesis of HVOs from CO_(2)hydrogenation.
基金Shandong Excellent Young Scientists Fund Program(Oversea),Grant/Award Number:2022S02002Jinan“5150”Talent Program,Grant/Award Number:2022C01001+1 种基金Pearl River Talent Recruitment Program,Grant/Award Number:2019QN01L096Guangdong Innovative and Entrepreneurial Research Team Program,Grant/Award Number:2019ZT08L075。
文摘The practical application of lithium–sulfur batteries(LSBs)is severely hindered by the undesirable shuttling of lithium polysulfides(LiPSs)and sluggish redox kinetics of sulfur species.Herein,a series of ultrathin singleatomic tungsten-doped Co_(3)O_(4)(Wx-Co_(3)O_(4))nanosheets as catalytic additives in the sulfur cathode for LSBs are rationally designed and synthesized.Benefiting from the enhanced catalytic activity and optimized electronic structure by W doping,the Wx-Co_(3)O_(4) not only reduces the shuttling of LiPSs but also decreases the energy barrier of sulfur redox reactions of sulfur species,leading to accelerated electrode kinetic.As a result,LSB cathodes with the use of 5.0 wt%W0.02-Co_(3)O_(4) as the electrocatalyst show the high reversible capacities of 1217.0 and 558.6 mAh g^(-1) at 0.2 and 5.0 C,respectively,and maintain a high reversible capacity of 644.6 mAh g^(-1) at 1.0 C(1.0 C=1675 mA g^(-1))after 500 cycles.With a high sulfur loading of 5.5 mg cm^(-2) and electrolyte–electrode ratio of 8μL_(electrolyte) mg_(sulfur)^(-1),the 5.0 wt%W_(0.02)-Co_(3)O_(4)-based sulfur cathode also retains a high reversible areal capacity of 3.86 mAh cm^(-2) at 0.1 C after 50 cycles with an initial capacity retention of 84.7%.
