Preparation of Modifiedsepiolite/Ru composite Electrode Materials for the performance and mechanism inelectrolytic-HER

Sepiolite converted into hierarchical porous carbon. • Ru nanoparticles anchored via C-O-Ru bonds. • 38 mV overpotential at 10 mA cm −2 . • SMSI tunes Ru electronic structure. • DFT confirms optimal ΔGH and adsorption. Ruthenium metal has been widely utilized as an efficient catalyst for hydrogen production electrocatalytic water splitting. However, its high cost and low atomic utilization efficiency are regarded as significant limitations for practical applications. In this study, Ru nanoparticles with sizes ranging from 2 to 10 nm were grown in situ onto the modified surface of sepiolite, a cheap mineral with limited electrical conductivity, via a low-cost synthetic strategy under mild conditions. The novelly synthesized catalyst shows a specific surface area of 422.1 m 2 /g with a pore volume of 0.213 cm 3 /g, and the multi-level pore structure of carbonized modified sepiolite is maintained. XPS and FTIR results indicate that abundant C-O-Ru functional groups. The synthesized composite exhibits excellent HER performance in acidic electrolytes, with an overpotential of 38 mV (at 10 mA/cm 2 current density), even lower than commercial platinum–carbon catalysts (39 mV). And stability of the catalyst is maintained after a 50-hour cycle, with a high-frequency region of the Nyquist diagram and minimal impedance arc diameter. Theoretical calculations also demonstrate that the synthesized catalyst exhibits considerable water adsorption capability (−0.925 eV) while maintaining a near-optimal ΔG H* value (−0.14 eV), which is favor of the Volmer step and efficient hydrogen desorption. Download: Download high-res image (150KB) Download: Download full-size image