Fabrication of dense spherical and rhombic Ti/Sb-SnO2 electrodes with enhanced electrochemical activity by colloidal electrodeposition

Two Ti/Sb-SnO2 electrodes with long service lifetime and excellent electrochemical decolorization performance were fabricated through direct current electrodeposition (Ti/Sb-SnO2-(c)DC) and pulsed electrodeposition (Ti/Sb-SnO2-(c)PED) techniques in a new colloidal medium, respectively. The scanning electron microscopy images demonstrated that the surface of the electrodes presented dense spherical and rhombic structures, respectively, which increased the electroactive surface area and oxygen evolution potential. Compared with Sb-doped SnO2 electrode prepared by electrodeposition in an aqueous solution (referred to as Ti/Sb-SnO2), the proposed electrodes had small crystal sizes (14.6 and 7.2 nm, respectively) and low charge exchange resistance (33.76 and 13.75 0, respectively). The colloidal electrodeposition prepared electrodes exhibited much higher stability than the Ti/Sb-SnO2 electrode. In a 0.25 M Na2SO4 solution, at a current density of 100 mA cm(-2), the accelerated lifetime of the Ti/Sb-SnO2-(c)DC (5.93 h) and Ti/Sb-SnO2-(c)PED (22.12 h) electrodes were 2.13 and 7.96 times longer, respectively, than that of Ti/Sb-SnO2 electrode (2.78 h). These SnO2 electrodes were demonstrated to have superior electrochemical decolorization ability for methyl orange. Compared with Ti/Sb-SnO2 electrode, the corresponding kinetic constants of Ti/Sb-SnO2-(c)DC and Ti/SbSnO2-(c)PED were 0.0255 and 0.0358 min(-1), respectively, which were 1.54 and 2.16 times that of the Ti/SbSnO2. After 120 min of electrolysis, methyl orange was completely decolorization on Ti/Sb-SnO2-(C)PED electrode. 2016 Elsevier B.V. All rights reserved.