Ti-induced construction of RuO2 solid solution for achieving high selectivity in ·OH generation and long lifespan electrocatalytic degradation of Methylene Blue

RuO 2 electrodes are widely used in electrocatalytic oxidation due to their excellent conductivity. However, their excessively high catalytic activity toward the oxygen evolution reaction (OER) results in low selectivity for hydroxyl radicals (·OH), which limits their application in the treatment of recalcitrant organic pollutants. This study proposes a strategy to simultaneously enhance electrode conductivity and the oxygen evolution potential (OEP) by modulating the RuO 2 -TiO 2 solid solution structure. Through precise control of Ti doping levels and calcination temperature via a sol-gel method, the structure-performance relationships among coating microstructure, crystal structure, and electrochemical behavior were systematically analyzed. Results show that when the Ti doping ratio is Ru: Ti= 1:2.5 and calcination is performed at 600 °C, a well-crystallized RuO 2 -TiO 2 solid solution is formed. This structure significantly reducing the charge transfer resistance and increasing the OEP by approximately 100 mV. Fluorescence and quenching experiments further confirmed that under this solid solution structure, with the ·OH fluorescence intensity increased by approximately ninefold compared to the undoped electrode. The electrode demonstrated significant advantages in MB degradation, achieving >95% decolorization within 30 min, with energy consumption as low as 5.65 kWh·t -1 , and exhibited stability more than ten times greater than that of conventional RuO 2 electrodes. This study provides a new perspective for enhancing the electrocatalytic performance of RuO 2 electrodes from the standpoint of solid solution structural regulation, offering a theoretical basis and a feasible pathway for developing efficient and low-cost anode materials for electrochemical advanced oxidation processes.