Engineering antibonding orbital occupancy of NiMoO4-supported Ru nanoparticles for enhanced chlorine evolution reaction

Chlorine evolution reaction (CER) is crucial for industrial-scale production of high-purity Cl 2 . Despite the development of classical dimensionally stable anodes to enhance CER efficiency, the competitive oxygen evolution reaction (OER) remains a barrier to achieving high Cl 2 selectivity. Herein, a binder-free electrode, Ru nanoparticles (NPs)-decorated NiMoO 4 nanorod arrays (NRAs) supported on Ti foam (Ru-NiMoO 4 /Ti), was designed for active CER in saturated NaCl solution (pH = 2). The Ru-NiMoO 4 /Ti electrode exhibits a low overpotential of 20 mV at 10 mA cm −2 current density, a high Cl 2 selectivity exceeding 90%, and robust durability for 90h operation. The marked difference in Tafel slopes between CER and OER indicates the high Cl 2 selectivity and superior reaction kinetics of Ru-NiMoO 4 /Ti electrode. Further studies reveal a strong metal-support interaction (SMSI) between Ru and NiMoO 4 , facilitating electron transfer through the Ru–O bridge bond and increasing the Ru 3d–Cl 2p antibonding orbital occupancy, which eventually results in weakened Ru–Cl bonding, promoted Cl desorption, and enhanced Cl 2 evolution. Our findings provide new insights into developing electrodes with enhanced CER performance through antibonding orbital occupancy engineering.