Ultrafast carbothermal shocking fabrication of cation vacancy-rich Mo doped Ru nanoparticles on carbon nanotubes for high-performance water/seawater electrolysis†

Abstract

Achieving the rapid synthesis of high-performance catalysts is of particular importance for realizing the industrialization of electrocatalytic water splitting. Herein, through a rapid carbothermal shocking method, we reported a superior electrocatalyst of cation vacancy-rich Mo doped Ru nanoparticles on carbon nanotubes (Mo–Ru/CNTs). Different from the chemical vapour deposition method, the rapid high-temperature synthesis can tailor lattice dislocations, formation of Ru vacancies, and reduction of the Ru valence state in Mo–Ru/CNTs. Theoretical analysis indicated that Ru vacancies and Mo doping on Ru nanoparticles can regulate the Ru–Ru bonds, optimize the d-orbital electronic structures and d-band center, and then facilitate H* adsorption on Ru sites. Furthermore, the CNTs can protect the Ru sites, and enhance the catalytic stability in the HER process. The as-prepared Mo–Ru/CNTs exhibited an excellent HER activity in both alkaline water (overpotential of 34.8 mV at 10 mA cm⁻²) and seawater (overpotential of 44.9 mV at 10 mA cm⁻²). Meanwhile, Mo–Ru/CNTs//RuO₂ only needed 1.52 V at 10 mA cm⁻² in an alkaline seawater electrolyzer for overall water splitting, and the energy consumption was even lower than that of the commercial 20% Pt/C//RuO₂. This study provided a new way to prepare highly active Ru-based catalysts for the HER in water/seawater via a rapid carbothermal shocking method.