The catalytic effects of the organic compounds of iron,tin and manganese on the degradation of low density polyethylene (LDPE) at compost temperature are discussed.A series of samples were aged in a simulating compost...The catalytic effects of the organic compounds of iron,tin and manganese on the degradation of low density polyethylene (LDPE) at compost temperature are discussed.A series of samples were aged in a simulating compost environment.The mechanical properties,viscosity average molecular weight (M η) of PE and hydroperoxide (POOH) concentration in the samples were measured.FT IR and DSC were also applied to characterize some samples.It was shown that the above mentioned metallic organic compounds can catalyze the degradation of LDPE efficiently.After 2 months aging,all samples with catalysts became fragile and the M η of the material decreased dramatically.Furthermore,the concentration of carbonyl and the degree of crystallinity of the material increased with the aging time.展开更多
Potassium-ion batteries(PIBs)represent one of the most promising alternatives to lithium-ion batteries(LIBs),owing to their exceptional attributes such as high voltages,potent power capabilities,and cost-effectiveness...Potassium-ion batteries(PIBs)represent one of the most promising alternatives to lithium-ion batteries(LIBs),owing to their exceptional attributes such as high voltages,potent power capabilities,and cost-effectiveness.Nonetheless,challenges arise from the sluggish kinetics and significant volume expansion observed during the insertion/extraction of large-radii potassium ions,leading to subpar rate performance and considerable capacity degradation in potassium-ion batteries.Consequently,it becomes imperative to explore advanced anode materials exhibiting high electrochemical activity and robust structural stability.In this regard,the present review focuses on recent progress in metal-organic compounds(MOCs)as anode materials for potassium-ion batteries,systematically discussing their outstanding merits from the perspective of metal speciation.Additionally,the principal mechanism of K ion storage within relevant MOCs is presented.Furthermore,a comprehensive summary of existing drawbacks that hinder the broader application of MOCs-based materials is provided,along with proposed guidelines and strategies for addressing the inferior performance characteristics.This review serves to illuminate the development of MOCs-based anode materials for potassium-ion batteries and offers a valuable reference for future research endeavors.展开更多
High-surface-area mesoprous powders of γ-Al2O3 doped with Cu^2＋, Cr^3＋, and V^3＋ ions were prepared uia a modified sol-gel method and were investigated as catalysts for the oxidation of chlorinated organic compoun...High-surface-area mesoprous powders of γ-Al2O3 doped with Cu^2＋, Cr^3＋, and V^3＋ ions were prepared uia a modified sol-gel method and were investigated as catalysts for the oxidation of chlorinated organic compounds. The composites retained high surface areas and pore volumes comparable with those of undoped γ-Al2O3 and the presence of the transition metal ions enhanced their surface acidic properties. The catalytic activity of the prepared catalysts in the oxidation of 1,2-dichloroethane （DCE） was studied in the temperature range of 250-400℃. The catalytic activity and product selectivity were strongly dependent on the presence and the type of dopant ion. While Cu^2＋- and Cr^3＋-containing catalysts showed 100% conversion at 300℃ and 350℃, V3＋-containing catalyst showed considerably lower conversion. Furthermore, while the major products of the reactions over γ-alumina were vinyl chloride （C2H3Cl） and hydrogen chloride （HCl） at all temperatures, Cu- and Cr-doped catalysts showed siguiticantly stronger capability for deep oxidation to CO2.展开更多
文摘The catalytic effects of the organic compounds of iron,tin and manganese on the degradation of low density polyethylene (LDPE) at compost temperature are discussed.A series of samples were aged in a simulating compost environment.The mechanical properties,viscosity average molecular weight (M η) of PE and hydroperoxide (POOH) concentration in the samples were measured.FT IR and DSC were also applied to characterize some samples.It was shown that the above mentioned metallic organic compounds can catalyze the degradation of LDPE efficiently.After 2 months aging,all samples with catalysts became fragile and the M η of the material decreased dramatically.Furthermore,the concentration of carbonyl and the degree of crystallinity of the material increased with the aging time.
基金the auspices of the National Natural Science Foundation of China(52277219,61974072).
文摘Potassium-ion batteries(PIBs)represent one of the most promising alternatives to lithium-ion batteries(LIBs),owing to their exceptional attributes such as high voltages,potent power capabilities,and cost-effectiveness.Nonetheless,challenges arise from the sluggish kinetics and significant volume expansion observed during the insertion/extraction of large-radii potassium ions,leading to subpar rate performance and considerable capacity degradation in potassium-ion batteries.Consequently,it becomes imperative to explore advanced anode materials exhibiting high electrochemical activity and robust structural stability.In this regard,the present review focuses on recent progress in metal-organic compounds(MOCs)as anode materials for potassium-ion batteries,systematically discussing their outstanding merits from the perspective of metal speciation.Additionally,the principal mechanism of K ion storage within relevant MOCs is presented.Furthermore,a comprehensive summary of existing drawbacks that hinder the broader application of MOCs-based materials is provided,along with proposed guidelines and strategies for addressing the inferior performance characteristics.This review serves to illuminate the development of MOCs-based anode materials for potassium-ion batteries and offers a valuable reference for future research endeavors.
基金United Arab Emirates University through NRF grant, 2011
文摘High-surface-area mesoprous powders of γ-Al2O3 doped with Cu^2＋, Cr^3＋, and V^3＋ ions were prepared uia a modified sol-gel method and were investigated as catalysts for the oxidation of chlorinated organic compounds. The composites retained high surface areas and pore volumes comparable with those of undoped γ-Al2O3 and the presence of the transition metal ions enhanced their surface acidic properties. The catalytic activity of the prepared catalysts in the oxidation of 1,2-dichloroethane （DCE） was studied in the temperature range of 250-400℃. The catalytic activity and product selectivity were strongly dependent on the presence and the type of dopant ion. While Cu^2＋- and Cr^3＋-containing catalysts showed 100% conversion at 300℃ and 350℃, V3＋-containing catalyst showed considerably lower conversion. Furthermore, while the major products of the reactions over γ-alumina were vinyl chloride （C2H3Cl） and hydrogen chloride （HCl） at all temperatures, Cu- and Cr-doped catalysts showed siguiticantly stronger capability for deep oxidation to CO2.
