pH electrodes based on iridium oxide films for marine monitoring

Abstract

The pH is an important parameter that affects the growth and development of marine organisms, environmental changes, and industrial and agricultural production processes. Nowadays, important trends in pH detection and analysis are higher stability, adaptation to extreme environmental conditions, miniaturization, portability, and digital intelligence. Several studies have focused on the application of the iridium oxide film (IROF) pH electrodes in water quality monitoring and physiological analysis. The central aim of this work was to review the preparation techniques of the IROF pH electrodes and to expand their application in the field of marine monitoring. The studied methods include electrochemical deposition, electrochemical growth, sputtering deposition, heat treatment, and novel preparation methods. The IROF pH electrodes prepared via these methods are more sensitive, have a wider pH measurement ranges, and can be miniaturized further than traditional glass and pH photometer. Hence, in environmental analysis, combining IROF pH electrodes with wireless technology for the physiological and biochemical analysis of marine organisms, seawater, and sediment pore water is an important development tendency.

Sol-Gel Coating Membranes for Optical Fiber Sensors for Concrete Structures Monitoring

“…To overcome the disadvantages of the glass bar, other alternatives were explored, such as the incorporation of structures with metal oxide as an active component and promising materials for new pH sensors. A pH response was considered for certain types of electrically conductive and semiconductor oxides [102][103][104][105] i.e., platinum, iridium, ruthenium, osmium dioxide, titanium, palladium, tin, zirconium, lead, rhodium oxides [106][107][108][109][110][111]. Iridium, ruthenium, and titanium oxides have been widely used in several applications, particularly in pH detection due to their fast response, chemical stability, high durability, and conductivity.…”

Preparation of nanopillar array electrode of iridium oxide for high performance of pH sensor and its real‐time sweat monitoring

“…electrodes make them unsuitable for wearable sensors. 28,29 Recently, flexible and miniaturized sensor electrodes have been developed based on organic and inorganic materials such as polyaniline, RuO 2 , IrO x , MnO 2 , TiO 2 , CuO, ZnO, and CeO 2 . [30][31][32][33][34][35][36] In particular, iridium oxide-based pH sensors exhibit excellent stability against dissolution, potential, and chemical stability, and super-Nernstian sensitivity (>65 mV/pH), higher than the theoretical Nernstian response (59 mV/pH at room temperature).…”

A Comparative Study of Fabricating IrOx Electrodes by High Temperature Carbonate Oxidation and Cyclic Thermal Oxidation and Quenching Process

“…Among the metal/metal oxides that could be used as H + detection material/pH electrode, including Pt/PtO 2 , W/WO 3 , RuO 2 , OsO 2 , IrO x , Ta 2 O 5 , SnO 2 , TiO 2 , Sb 2 O 3 , or a mixture of two kinds of oxides [1][2][3][4], iridium oxide is one of the most promising by evaluating the response range, Nernst response sensitivity, potential drift behavior, interference of reduction and oxidation.…”