Cuprous oxide(Cu2O)is an attractive material for photoelectrochemical(PEC)hydrogen production or photovoltaic application,because of its appropriate band gap,low material cost and non-toxic.In this paper,Cu2O films we...Cuprous oxide(Cu2O)is an attractive material for photoelectrochemical(PEC)hydrogen production or photovoltaic application,because of its appropriate band gap,low material cost and non-toxic.In this paper,Cu2O films were obtained by comproportionation in acid cupric sulfate solutions with varying concentrations of potassium nitrate.Photoelectrochemical and electrochemical experiments,such as zero-bias photocurrent responses,voltammograms,and Mott-Schottky measurements,show that the Cu2O films grown in low(≤0.75 mol dm^–3)and high(≥1.00 mol dm^–3)nitrate ion concentrations presented n-type and p-type conductivity,respectively.Open circuit potential and polarization behavior were monitored to investigate the mechanism of modulating conductivity type.Nitrate ions consume protons in the plating solution during comproportionation with different concentrations of nitrate ions creating different pH at the Cu2O/solution interface.This gradient leads to the transformation of Cu2Ofilms conductivity changing from n-type to p-type with increasing the concentration of nitrate ions in the plating solution.This method could be used to fabricate homojunction electrode on metal substrate for PEC hydrogen production or photoelectric application.展开更多
Minor-adjustment of the retention of peptides, induced by varying the mobile phase flow-rate(MPF-R), is a new dynamic separation method for simultaneously and rapidly identifying and improving the selectivity of hidde...Minor-adjustment of the retention of peptides, induced by varying the mobile phase flow-rate(MPF-R), is a new dynamic separation method for simultaneously and rapidly identifying and improving the selectivity of hidden and overlapping peptide peaks. It can also-stabilize the reverse elution order of some pair-peaks under gradient elution in reverse phase liquid chromatography. The retention characteristics of peptides under gradient elution in RPLC was firstly found to be dominated by two variables of the steady region(SR) and migration region(MR). The changes in peptide retention induced by varying the MPF-R can be attributed to changes in the rate of bond breaking of multiple molecular interactions of peptides from the SR and of the mass transfer of peptides from the stationary phase to the mobile phase in the MR. The two dynamic variables were also found to independently depend on the type of peptide. Desirable results were obtained using six standard oligopeptides and a real sample of trypsin-digested lysozyme.It is expected that the quality control of peptide drugs, high dispersion of peptide peaks in peptide mapping and "bottom-up MS"in proteomics will be improved by this method, even enabling peptide purification on a preparative scale in industry.展开更多
基金financially supported by the National Natural Science Foundation of China (No. 51302216 and 21375102)the Excellent Young Academic Backbone Program of the Northwest University+1 种基金the Open Fund of the State Key Laboratory of Multiphase Flow in Power Engineering of Chinathe Scientific Research Program funded by Shaanxi Provincial Education Department (No. 17JS121)
文摘Cuprous oxide(Cu2O)is an attractive material for photoelectrochemical(PEC)hydrogen production or photovoltaic application,because of its appropriate band gap,low material cost and non-toxic.In this paper,Cu2O films were obtained by comproportionation in acid cupric sulfate solutions with varying concentrations of potassium nitrate.Photoelectrochemical and electrochemical experiments,such as zero-bias photocurrent responses,voltammograms,and Mott-Schottky measurements,show that the Cu2O films grown in low(≤0.75 mol dm^–3)and high(≥1.00 mol dm^–3)nitrate ion concentrations presented n-type and p-type conductivity,respectively.Open circuit potential and polarization behavior were monitored to investigate the mechanism of modulating conductivity type.Nitrate ions consume protons in the plating solution during comproportionation with different concentrations of nitrate ions creating different pH at the Cu2O/solution interface.This gradient leads to the transformation of Cu2Ofilms conductivity changing from n-type to p-type with increasing the concentration of nitrate ions in the plating solution.This method could be used to fabricate homojunction electrode on metal substrate for PEC hydrogen production or photoelectric application.
基金supported by the Foundation of Provincial Key Laboratory of Modern Separation Science (12JS091, 13JS117, 14JS096)
文摘Minor-adjustment of the retention of peptides, induced by varying the mobile phase flow-rate(MPF-R), is a new dynamic separation method for simultaneously and rapidly identifying and improving the selectivity of hidden and overlapping peptide peaks. It can also-stabilize the reverse elution order of some pair-peaks under gradient elution in reverse phase liquid chromatography. The retention characteristics of peptides under gradient elution in RPLC was firstly found to be dominated by two variables of the steady region(SR) and migration region(MR). The changes in peptide retention induced by varying the MPF-R can be attributed to changes in the rate of bond breaking of multiple molecular interactions of peptides from the SR and of the mass transfer of peptides from the stationary phase to the mobile phase in the MR. The two dynamic variables were also found to independently depend on the type of peptide. Desirable results were obtained using six standard oligopeptides and a real sample of trypsin-digested lysozyme.It is expected that the quality control of peptide drugs, high dispersion of peptide peaks in peptide mapping and "bottom-up MS"in proteomics will be improved by this method, even enabling peptide purification on a preparative scale in industry.
