Enhancing Ru-Cl interaction via orbital hybridization effect in RuSnTi electrode for efficient chlorine evolution.

Chlorine evolution reaction (CER) is a commercially valuable electrochemical reaction used at an industrial scale. However, oxygen evolution reaction (OER) during the electrolysis process inevitably leads to the decreased efficiency of CER. It is necessary to improve the selectivity of CER by minimizing or even eliminating the occurrence of OER. Herein, a ternary metal oxide (RuSnTi) electrode was fabricated and employed as an active and robust anode for CER. The RuSnTi electrode exhibits an excellent CER performance in 6.0 M NaCl solution, with a low potential of 1.17 V (vs. saturated calomel electrode, SCE) at 200 mA cm current density, a high Cl selectivity of over 90 %, and robust durability after consecutive operation for 160 h under 100 mA cm. The maximum O-Cl potential difference between OER and CER further demonstrates the high Cl selectivity of RuSnTi electrode. Theoretical studies show that the strong Ru 3d-Ti 3d orbitals hybridization effect makes the d-band center (ε) of Ru 3d and Ti 3d orbitals positively and negatively shifted, respectively, endowing Ru site with enhanced Cl adsorption ability (i.e. enhanced Ru-Cl interaction) and RuSnTi electrode with superior CER activity. This work offers valuable insights into the development of advanced electrodes for CER in practical application.