An activated carbon(AC)supported Pd catalyst was used to develop a highly efficient in situ adsorption-catalysis system for the removal of low concentrations of o-xylene.In this study,three kinds of Pd/AC catalysts we...An activated carbon(AC)supported Pd catalyst was used to develop a highly efficient in situ adsorption-catalysis system for the removal of low concentrations of o-xylene.In this study,three kinds of Pd/AC catalysts were prepared and tested to investigate the synergistic efficiency between adsorption and catalysis for o-xylene removal.The Pd/AC catalyst was first used as an adsorbent to concentrate dilute o-xylene at low temperature.After saturated adsorption,the adsorbed o-xylene was oxidized to CO_(2)and H20 by raising the temperature of the catalyst bed.The results showed that more than 99%of the adsorbed o-xylene was completely oxidized to CO_(2)over a 5%Pd/AC catalyst at 140℃.Brunauer-Emmett-Teller(BET)analysis,scanning electron microscopy(SEM),temperatureprogrammed desorption(TPD),and temperature-programmed oxidation(TPO)were applied to investigate the physical properties of o-xylene adsorption-desorption and the in situ adsorption-catalysis activity of the AC support and Pd/AC catalyst.A synergistic relationship between the AC support and the active Pd species for the removal of low concentrations of o-xylene was established.展开更多
The polysulfide shuttling and sluggish redox kinetics,due to the notorious adsorption-catalysis underperformance,are the ultimate obstacles of the practical application of lithium-sulfur(Li-S)batteries.Conventional ca...The polysulfide shuttling and sluggish redox kinetics,due to the notorious adsorption-catalysis underperformance,are the ultimate obstacles of the practical application of lithium-sulfur(Li-S)batteries.Conventional carbon-based and transition metal compound-based material solutions generally suffer from poor catalysis and adsorption,respectively,despite the performance gain in terms of the other.Herein,we have enhanced polysulfide adsorptioncatalytic capability and protected the Li anode using a complementary bimetallic carbide electrocatalyst,Co3 Mo3 C,modified commercial separator.With this demonstration,the potentials of bimetal compounds,which have been well recognized in other environmental catalysis,are also extended to Li-S batteries.Coupled with this modified separator,a simple cathode(S/Super P composite)can deliver high sulfur utilization,high rate performance,and excellent cycle stability with a low capacity decay rate of^0.034%per cycle at 1 C up to1000 cycles.Even at a high S-loading of 8.0 mg cm^-2 with electrolyte/sulfur ratio=6 m L g^-1,the cathode still exhibits high areal capacity of^6.8 m A h cm^-2.The experimental analysis and the first-principles calculations proved that the bimetallic carbide Co3 Mo3 C provides more binding sites for adsorbing polysulfides and catalyzing the multiphase conversion of sulfur/polysulfide/sulfide than monometallic carbide Mo2 C.Moreover,the modified separator can be reutilized with comparable electrochemical performance.We also showed other bimetallic carbides with similar catalytic effects on Li-S batteries and this material family has great promise indifferent energy electrocatalytic systems.展开更多
基金supported by the National Natural Science Foundation of China(No.20607029)the Ministry of Science and Technology of China(No.2007AA061402)
文摘An activated carbon(AC)supported Pd catalyst was used to develop a highly efficient in situ adsorption-catalysis system for the removal of low concentrations of o-xylene.In this study,three kinds of Pd/AC catalysts were prepared and tested to investigate the synergistic efficiency between adsorption and catalysis for o-xylene removal.The Pd/AC catalyst was first used as an adsorbent to concentrate dilute o-xylene at low temperature.After saturated adsorption,the adsorbed o-xylene was oxidized to CO_(2)and H20 by raising the temperature of the catalyst bed.The results showed that more than 99%of the adsorbed o-xylene was completely oxidized to CO_(2)over a 5%Pd/AC catalyst at 140℃.Brunauer-Emmett-Teller(BET)analysis,scanning electron microscopy(SEM),temperatureprogrammed desorption(TPD),and temperature-programmed oxidation(TPO)were applied to investigate the physical properties of o-xylene adsorption-desorption and the in situ adsorption-catalysis activity of the AC support and Pd/AC catalyst.A synergistic relationship between the AC support and the active Pd species for the removal of low concentrations of o-xylene was established.
基金supported by the National Natural Science Foundation of China(21863006,51662029,61974082 and 61704096)Youth Science Foundation of Jiangxi Province(20192BAB216001)Key Laboratory of Jiangxi Province for Environment and Energy Catalysis(20181BCD40004)。
文摘The polysulfide shuttling and sluggish redox kinetics,due to the notorious adsorption-catalysis underperformance,are the ultimate obstacles of the practical application of lithium-sulfur(Li-S)batteries.Conventional carbon-based and transition metal compound-based material solutions generally suffer from poor catalysis and adsorption,respectively,despite the performance gain in terms of the other.Herein,we have enhanced polysulfide adsorptioncatalytic capability and protected the Li anode using a complementary bimetallic carbide electrocatalyst,Co3 Mo3 C,modified commercial separator.With this demonstration,the potentials of bimetal compounds,which have been well recognized in other environmental catalysis,are also extended to Li-S batteries.Coupled with this modified separator,a simple cathode(S/Super P composite)can deliver high sulfur utilization,high rate performance,and excellent cycle stability with a low capacity decay rate of^0.034%per cycle at 1 C up to1000 cycles.Even at a high S-loading of 8.0 mg cm^-2 with electrolyte/sulfur ratio=6 m L g^-1,the cathode still exhibits high areal capacity of^6.8 m A h cm^-2.The experimental analysis and the first-principles calculations proved that the bimetallic carbide Co3 Mo3 C provides more binding sites for adsorbing polysulfides and catalyzing the multiphase conversion of sulfur/polysulfide/sulfide than monometallic carbide Mo2 C.Moreover,the modified separator can be reutilized with comparable electrochemical performance.We also showed other bimetallic carbides with similar catalytic effects on Li-S batteries and this material family has great promise indifferent energy electrocatalytic systems.
