Fig. 2: Temperature effect on the CE between the SiO2 and aqueous solutions.

(a) The effects of the NaCl concentration on the CE between the SiO2 and the NaCl solutions. (b) The decay of the CE charge at 433 K which is induced by contacting with the NaCl solutions. (c) The CE charge density on the SiO2 sample surface in the charging (contacting with 0.4 M NaCl solution at room temperature) and heating (513 K for 10 min) cycle tests. (d) The decay of the CE charge at 433 K, which is induced by contacting with the pH 11 HCl solution and the pH 3 NaOH solution. The charging and heating cycle testes when the liquids are (e) the pH 11 NaOH solution and (f) the pH 3 HCl solution. (Error bar are defined as s. d.).