Hyperdispersed ruthenium nanoparticles anchored on S/N co-doped carbon nanotubes as an efficient HER electrocatalyst

Abstract

The preparation of green hydrogen by electrolyzing water has shown great application prospects, and the noble metal Pt as a catalyst for the hydrogen evolution reaction (HER) is one of the main factors hindering its large-scale development. Therefore, efforts to develop low-cost catalysts are currently on-going in many laboratories. Herein, we used hydroxylated carbon nanotubes as starting materials and doped them with heteroatoms (S and N) to create catalytic active sites. In order to further improve the catalytic performance of the material, ruthenium nanoparticles were embedded on the nanotubes to obtain an excellent HER catalyst (Ru@S/N/CNT). We have systematically analyzed its morphology, chemical composition and electrochemical properties. The results show that its HER catalytic performance is outstanding, even higher than that of commercial Pt/C. Ru@S/N/CNTs show excellent catalytic performance under both acidic and alkaline conditions, which is due to the synergistic effect of the doping strategy and ruthenium nanoparticles. In 0.5 M H₂SO₄, the overpotential is 68 mV (10 mA cm⁻²), and the Tafel slope is only 44 mV dec⁻¹. In 1 M KOH, the overpotential is only 9 mV at 10 mA cm⁻², and the Tafel slope is only 37 mV dec⁻¹. The doping strategy can only improve the catalytic performance of the material to a certain extent, and the SCN⁻ poisoning experiment shows that dispersed ruthenium nanoparticles play a major role in HER catalysis.