Europium doped RuO2@TP enhanced chlorine evolution reaction performance by charge redistribution

Abstract

The chlorine evolution reaction (CER) plays a significant role in the generation of Cl2 and active chlorine during chlor-alkali electrolysis. However, CER competing with oxygen evolution reaction (OER) on the anode side always suffers from low selectivity due to the adsorption of OCl and OOH intermediates on active sites. Herein, Eu-doped RuO2 catalysts on Ti plate (TP) with excellent CER performance is reported by the rational design of doping rare earth metal Eu into RuO2, which induces a strong charge redistribution between Eu and Ru and tunes the adsorption ability. The representative Ru0.9Eu0.1Ox@TP reveals a yield of active chlorine of 12.8 mg h−1 with a high selectivity of 96.5% toward CER at 20 mA cm−2, and a mass activity of about 2.94 times higher than that on Ru-based DSA in 0.5 M chloride-containing solution. Additionally, Ru0.9Eu0.1Ox@TP shows a robust stability of over 225 h at 1000 mA cm−2 in 0.5 M of H2SO4. The microstructural characterizations and density functional theory (DFT) reveal that doping Eu into RuO2 decreases the charge on Ru sites, thus enhancing the adsorption ability with OCl and supressing OOH. In addition, Ru0.9Eu0.1Ox@TP exhibits the activity toward NH4+-N removal rate with a degradation rate of 95% in 1 h at 20 mA cm−2, suggesting its potential application for waste-water treatment. Moreover, the expected service life of the electrode is estimated to exceed 13.4 years.