Catalytic Activity of Nanosized Ruthenium Oxide-Coated Titanium Anodes Prepared by Thermal Decomposition for Oxygen Evolution in Sulfuric Acid Solutions

The effects of the nanoscale particle size of RuO2 in thermally prepared RuO2-coated Ti anodes on electrochemical kinetic parameters such as the active surface area and Tafel slope for oxygen evolution in sulfuric acid solutions were investigated. RuO2/Ti anodes with four different average sizes of RuO2 particles-5.6 nm, 6.8 nm, 14.6 nm, and 21.2 nm-were prepared. The double-layer charge corresponding to the active surface area for oxygen evolution of the anodes was shown to increase with decreasing average RuO2 particle size. The polarization curves of the anodes showed that the oxygen evolution current density at a certain potential increased with decreasing average RuO2 particle size, meaning that oxygen evolution, especially in the high-current-density region, where it mainly depends on the mass transfer rate, accelerated with decreasing RuO2 particle size. The Tafel slope obtained for the anodes was shown to decrease with decreasing average RuO2 particle size, indicating that the change in particle size affected the electron transfer rate for oxygen evolution. The present study reveals that changes in the nanoscale size of RuO2 affect not only the mass transfer process but also the electron transfer process for oxygen evolution in sulfuric acid solutions.

Automated summary

The nanoscale particle size of RuO2 in thermally prepared RuO2-coated Ti anodes affects the electrochemical kinetic parameters such as the active surface area and Tafel slope for oxygen evolution in sulfuric acid solutions. Decreasing RuO2 particle size leads to increased double-layer charge corresponding to the active surface area, higher oxygen evolution current density at a certain potential, and a decrease in Tafel slope, indicating changes in particle size influence both mass transfer and electron transfer processes during oxygen evolution in sulfuric acid solutions.