The MgO samples are prepared by heating Mg(OH) 2 at 600 ℃ in different atmospheres. The XRD results show that Mg(OH) 2 is decomposed into MgO after calcination. The results of BET indicate that the specific surface a...The MgO samples are prepared by heating Mg(OH) 2 at 600 ℃ in different atmospheres. The XRD results show that Mg(OH) 2 is decomposed into MgO after calcination. The results of BET indicate that the specific surface area of the samples is affected by the calcination atmosphere, the sample preheated in vacuum has the highest surface area, while the sample preheated in air has the lowest surface area. The CO 2 TPD profiles of the samples are also different, which implies that the samples have different surface basicity. From the desorbed amount of CO 2 and the desorption activation energy, it is found that the sample pretreated in vacuum has the most basic sites and the strongest basicity.展开更多
The self assembled monolayer(SAM) of 11 mercaptoundecanoic acid [HS(CH 2) 10 COOH] was formed on a gold electrode and the effect of the charge of end group on the electrochemical response of Fe(CN) 3- 6 at the SAM mod...The self assembled monolayer(SAM) of 11 mercaptoundecanoic acid [HS(CH 2) 10 COOH] was formed on a gold electrode and the effect of the charge of end group on the electrochemical response of Fe(CN) 3- 6 at the SAM modified electrode was studied by cyclic voltammetry. At high pH, when the —COOH groups are dissociated, the current of Fe(CN) 3- 6 is suppressed; as the solution pH is lowered, the current of Fe(CN) 3- 6 increases. The electrochemical titration curve was obtained by correlating the currents of Fe(CN) 3- 6 to the different pH values of electrolyte, from which the surface p K a was obtained to be 3.0±0.2. Furthermore, the reason of small p K a value was explained using SAMs of different surface coverage.展开更多
文摘The MgO samples are prepared by heating Mg(OH) 2 at 600 ℃ in different atmospheres. The XRD results show that Mg(OH) 2 is decomposed into MgO after calcination. The results of BET indicate that the specific surface area of the samples is affected by the calcination atmosphere, the sample preheated in vacuum has the highest surface area, while the sample preheated in air has the lowest surface area. The CO 2 TPD profiles of the samples are also different, which implies that the samples have different surface basicity. From the desorbed amount of CO 2 and the desorption activation energy, it is found that the sample pretreated in vacuum has the most basic sites and the strongest basicity.
文摘The self assembled monolayer(SAM) of 11 mercaptoundecanoic acid [HS(CH 2) 10 COOH] was formed on a gold electrode and the effect of the charge of end group on the electrochemical response of Fe(CN) 3- 6 at the SAM modified electrode was studied by cyclic voltammetry. At high pH, when the —COOH groups are dissociated, the current of Fe(CN) 3- 6 is suppressed; as the solution pH is lowered, the current of Fe(CN) 3- 6 increases. The electrochemical titration curve was obtained by correlating the currents of Fe(CN) 3- 6 to the different pH values of electrolyte, from which the surface p K a was obtained to be 3.0±0.2. Furthermore, the reason of small p K a value was explained using SAMs of different surface coverage.
