Work

Confining Flat Ru Islands into TiO 2 Lattice with the Coexisting Ru–O–Ti and Ru–Ti Bonds for Ultra‐Stable Hydrogen Evolution at Amperometric Current Density and Hydrogen Oxidation at High Potential

Year: 2024

Type: article

Abstract: Effective hydrogen evolution reaction (HER) under high current density and enhanced hydrogen oxidation reaction (HOR) over a wide potential range remain challenges for Ru‐based electrocatalysts because its strong affinity to the adsorbed hydroxyl (OH ad ) inhibits the supply of the adsorbed hydrogen (H ad ). Herein, the coexisting Ru─O─Ti and Ru─Ti bonds are constructed by taking TiO 2 crystal confined flat‐Ru clusters (F‐Ru@TiO 2 ) to cope with above‐mentioned obstacles. The different electronegativity (χ Ti = 1.54 < χ Ru = 2.20< χ O = 3.44) can endow Ti in Ru─O─Ti bonds with more positive charge and stabilize Ru of Ru–Ti bonds with the low‐valence. The strength of Ru─OH ad is then weakened by the oxophilicity of positively charged Ti in Ru─O─Ti bonds and the stronger Ti─OH ad bond could release active Ru, especially for low‐valence Ru in Ru─Ti bonds, to serve as exclusive H ad sites. As expected, F─TiRu@TiO 2 shows a low HER overpotential of 74 mV at 1000 mA cm −2 and an ultrahigh mass activity (j 0,m ) of 3155 A g Ru −1 for HOR. More importantly, F─Ru@TiO 2 can tolerate the HER current density of 1000 mA cm −2 for 100 h and the high anodic potential for HOR up to 0.5 V versus RHE.

Source: Advanced Science

DOI: 10.1002/advs.202410881