Platinum was electrodeposited onto a polyaniline-modified carbon fiberelectrode by the cyclic voltammetric method in sulfuric acid, which may enable an increase in thelevel of platinum utilization currently achieved i...Platinum was electrodeposited onto a polyaniline-modified carbon fiberelectrode by the cyclic voltammetric method in sulfuric acid, which may enable an increase in thelevel of platinum utilization currently achieved in electrocatalytic systems. This electrodepreparation consists of a two-step procedure: first electropolymerization of aniline onto carbonfiber and then electrodeposition of platinum. The catalytic activity of theplatinum-polyanihne-modified carbon fiber electrode (Pt/PAni/C) was compared with that of a barecarbon fiber electrode (Pt/C) by the oxidation of methanol. The maximum oxidation current ofmethanol on Pt/PAni/C is 50.7 mA centre dot cm^(-2), which is 6.7 times higher than 7.6 mA centredot cm^(-2) on the Pt/C. Scanning electron microscopy was used to investigate the dispersion of theplatinum particles of about 0.4 um.展开更多
The time-convolutionless （TCL） quantum master equation provides a powerful tool to simulate reduced dynanfics of a quantum system coupled to a bath. The key quantity ill the TCL master equation is the so-called kern...The time-convolutionless （TCL） quantum master equation provides a powerful tool to simulate reduced dynanfics of a quantum system coupled to a bath. The key quantity ill the TCL master equation is the so-called kernel or generator, which describes eflhcts of the bath degrees of freedom. Since the exact TCL generators are usually hard to calculate analytically, most applications of the TCL generalized master equation have relied on approximate generators using second and fourth order perturbative expansions. By using the hierarchical equation of motion （HEOM） and extended HEOM methods, we present a new approach to calculating the exact TCL generator and its high order perturbative expansions. The new approach is applied to the spin-boson model with diflhrent sets of parameters, to investigate the convergence of the high order expansiolls of the TCL generator. We also discuss circumstances where the exact TCL generator becomes singular for the spin-boson model, and a model of excitation energy transfer in the Fenna-Matthews-Olson complex.展开更多
文摘Platinum was electrodeposited onto a polyaniline-modified carbon fiberelectrode by the cyclic voltammetric method in sulfuric acid, which may enable an increase in thelevel of platinum utilization currently achieved in electrocatalytic systems. This electrodepreparation consists of a two-step procedure: first electropolymerization of aniline onto carbonfiber and then electrodeposition of platinum. The catalytic activity of theplatinum-polyanihne-modified carbon fiber electrode (Pt/PAni/C) was compared with that of a barecarbon fiber electrode (Pt/C) by the oxidation of methanol. The maximum oxidation current ofmethanol on Pt/PAni/C is 50.7 mA centre dot cm^(-2), which is 6.7 times higher than 7.6 mA centredot cm^(-2) on the Pt/C. Scanning electron microscopy was used to investigate the dispersion of theplatinum particles of about 0.4 um.
基金supported by the National Natural Science Foundation of China(No.21673246)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB12020300)
文摘The time-convolutionless （TCL） quantum master equation provides a powerful tool to simulate reduced dynanfics of a quantum system coupled to a bath. The key quantity ill the TCL master equation is the so-called kernel or generator, which describes eflhcts of the bath degrees of freedom. Since the exact TCL generators are usually hard to calculate analytically, most applications of the TCL generalized master equation have relied on approximate generators using second and fourth order perturbative expansions. By using the hierarchical equation of motion （HEOM） and extended HEOM methods, we present a new approach to calculating the exact TCL generator and its high order perturbative expansions. The new approach is applied to the spin-boson model with diflhrent sets of parameters, to investigate the convergence of the high order expansiolls of the TCL generator. We also discuss circumstances where the exact TCL generator becomes singular for the spin-boson model, and a model of excitation energy transfer in the Fenna-Matthews-Olson complex.
