Catalyst plays an important role in the dehydration of N-（hydroxylethyl）pyrrolidone （NHP） to prepare N-vinyl-pyrrolidone （NVP）. At present, NVP yield is only about 30% on commercial ZrO2 catalyst. A coupled prec...Catalyst plays an important role in the dehydration of N-（hydroxylethyl）pyrrolidone （NHP） to prepare N-vinyl-pyrrolidone （NVP）. At present, NVP yield is only about 30% on commercial ZrO2 catalyst. A coupled precipitation and solid dispersion technique was designed to prepare the nano-ZrO2 catalyst, in which rare earth metal oxides （REOx） was used as electronic promoter. The results indicated that the catalyst doped REOx （S-1.0） exhibits the optimum performance of NHP dehydration at moderate conditions. NHP conversion and NVP selectivity are respectively 97.0%, 82.3%. Of special interest is that the indexes of the catalyst （S-1.0-1.0） are up to 98.4% and 89.2% respectively. Furthermore, this catalyst bears the good stability. It means that nano-ZrO2 doped REOx catalyst might be a potential commercial catalyst for the NHP dehydration.展开更多
The electronic structure of catalytic active sites can be influenced by modulating the coordination bonding of the central single metal atom,but it is difficult to achieve.Herein,we reported the single Zn-atom incorpo...The electronic structure of catalytic active sites can be influenced by modulating the coordination bonding of the central single metal atom,but it is difficult to achieve.Herein,we reported the single Zn-atom incorporated dual doped P,N carbon framework(Zn-N_(4)P/C)for ORR via engineering the surrounding coordination environment of active centers.The Zn-N_(4)P/C catalyst exhibited comparable ORR activity(E_(1/2)=0.86 V)and significantly better ORR stability than that of Pt/C catalyst.It also shows respectable performance in terms of maximum peak power density(249.6 mW cm^(-2)),specific capacitance(779 mAh g^(-1)),and charge-discharge cycling stability for 150 hours in Zn-air battery.The high catalytic activity is attributed to the uniform active sites,tunable electronic/geometric configuration,optimized intrinsic activity,and faster mass transfer during ORR-pathway.Further,theoretical results exposed that the Zn-N_(4)P configuration is more electrochemically active as compared to Zn-N_(4) structure for the oxygen reduction reaction.展开更多
The conceptual ideas about the positive effects of N- and O-heteroatoms on the reactivity of carbons in gasification processes, their catalytic activity in electron transfer reactions, as well as the performance of th...The conceptual ideas about the positive effects of N- and O-heteroatoms on the reactivity of carbons in gasification processes, their catalytic activity in electron transfer reactions, as well as the performance of the electrode double-layer supercapacitors due to their electron-donating influence on the 7r-conjugated system of graphene layers have been developed. This influence decreases both work function and band gap of carbons, and also significantly affects their electron-donating properties. As a result of our investigations based on quantum chemical calculations of model graphene clusters with N- and O-heteroatoms in different positions, prognostic data have been obtained. These data have been confirmed by our experimental results of catalytic activity of corresponding carbons in H202 decomposition reaction, their reactivity in gasification processes, and also their performance as electrodes in supercapacitors.展开更多
文摘Catalyst plays an important role in the dehydration of N-（hydroxylethyl）pyrrolidone （NHP） to prepare N-vinyl-pyrrolidone （NVP）. At present, NVP yield is only about 30% on commercial ZrO2 catalyst. A coupled precipitation and solid dispersion technique was designed to prepare the nano-ZrO2 catalyst, in which rare earth metal oxides （REOx） was used as electronic promoter. The results indicated that the catalyst doped REOx （S-1.0） exhibits the optimum performance of NHP dehydration at moderate conditions. NHP conversion and NVP selectivity are respectively 97.0%, 82.3%. Of special interest is that the indexes of the catalyst （S-1.0-1.0） are up to 98.4% and 89.2% respectively. Furthermore, this catalyst bears the good stability. It means that nano-ZrO2 doped REOx catalyst might be a potential commercial catalyst for the NHP dehydration.
文摘The electronic structure of catalytic active sites can be influenced by modulating the coordination bonding of the central single metal atom,but it is difficult to achieve.Herein,we reported the single Zn-atom incorporated dual doped P,N carbon framework(Zn-N_(4)P/C)for ORR via engineering the surrounding coordination environment of active centers.The Zn-N_(4)P/C catalyst exhibited comparable ORR activity(E_(1/2)=0.86 V)and significantly better ORR stability than that of Pt/C catalyst.It also shows respectable performance in terms of maximum peak power density(249.6 mW cm^(-2)),specific capacitance(779 mAh g^(-1)),and charge-discharge cycling stability for 150 hours in Zn-air battery.The high catalytic activity is attributed to the uniform active sites,tunable electronic/geometric configuration,optimized intrinsic activity,and faster mass transfer during ORR-pathway.Further,theoretical results exposed that the Zn-N_(4)P configuration is more electrochemically active as compared to Zn-N_(4) structure for the oxygen reduction reaction.
文摘The conceptual ideas about the positive effects of N- and O-heteroatoms on the reactivity of carbons in gasification processes, their catalytic activity in electron transfer reactions, as well as the performance of the electrode double-layer supercapacitors due to their electron-donating influence on the 7r-conjugated system of graphene layers have been developed. This influence decreases both work function and band gap of carbons, and also significantly affects their electron-donating properties. As a result of our investigations based on quantum chemical calculations of model graphene clusters with N- and O-heteroatoms in different positions, prognostic data have been obtained. These data have been confirmed by our experimental results of catalytic activity of corresponding carbons in H202 decomposition reaction, their reactivity in gasification processes, and also their performance as electrodes in supercapacitors.
