Fabrication of thick film sensitive RuO2-TiO2 and Ag/AgCl/KCl reference electrodes and their application for pH measurements

TiO2-Based Thick Film pH Sensor

“…In an impedancemetric and/or conductimetric based sensor, any changes that occur on the surface of the sensitive electrode while reacting with solution, changes the electrical properties of the sensor [2,14,23,31]. For a constant pH, we see decrease in the impedance and increase in phase as the frequency increases.…”

“…The fabrication procedure of the conductimetric pH was similar to that reported in [2,23]. We chose alumina as a substrate to investigate the performance of pure metal oxide and to avoid any reaction at metal-metal oxide interface.…”

“…These changes in impedance and phase of TiO 2 based sensor can be attributed to electrochemical surface reaction of H + /OH -ions with the oxide surface. When a metal oxide is introduced into an electrolyte, many electrochemical reactions occur at the oxide-solution surface [2,23]. In the case of TiO 2 , the dissociative chemisorption of water molecule results in the formation of surface hydroxyl group [15].…”

“…as pH sensitive electrode. The poor cost-effectiveness of RuO 2 and IrO 2 based sensors [12,13], low resistance of RuO 2 in alkaline solutions (which affect their lifetime) [12,13], and buffer on the conductance in SnO 2 based conductimetric pH sensor [14]. etc.…”

“…One example is the conductimetric pH sensor developed by Chen et al [17], which is based on TiO 2 /multiwall carbon nanotube (MWCNT)/cellulose hybrid nanocomposite. The fabricated sensor exhibited sensitivity in the pH range of [1][2][3][4][5][6][7][8][9][10][11][12]. A large surface area of cellulose hybrid nanocomposite helps improve the pH sensitivity [17].…”