Hydrous RuO 2 nanoparticles as highly active electrocatalysts for hydrogen evolution reaction

Ruthenium Nanoparticles for Catalytic Water Splitting

“…Several authors have also studied the effect of the degree of crystallinity of the employed Ru‐based NPs on the OER . Lim and co‐workers recently reported the inferior efficiency (123 mV higher η 0 ) and stability of hydrous RuO 2 particles of low crystallinity, with regard to those of its crystalline counterpart (prepared by annealing of the former at 300 °C) in 1 m KOH (Table , entries 2 and 3) . In terms of overpotentials, this result differs from the results described for RuO 2 thin films .…”

“…Nonsupported Ru‐based NPs have been prepared through a myriad of methods, such as the thermal decomposition/calcination of anhydrous RuO 2 , Ru salt, or a Ru complex; or through the electroreduction of a Ru salt, Ru perovskite‐type precursor, or Ru complex . However, the tailored synthesis and rational catalytic fine‐tuning of nonsupported Ru‐based NPs is not a simple matter.…”

“…The degree of crystallinity is another critical issue that controls the activity and stability of NP nonsupported Ru‐based HER electrocatalysts, which, as stated above for the OER, has not been thoroughly studied. Concerning RuO 2 NPs, the works of Lim et al . and Song et al .…”

“…The first set of Ru‐based electrolyzers for the whole WS process involve the use of RuO 2 NPs as both the anode and cathode. For instance, Lim and co‐workers reported a hydrous/crystalline RuO 2 bifunctional electrocatalyst and its integration into an efficient cell for the overall splitting of water . These authors reported the combination of a cathode composed of stable hydrous RuO 2 NPs/Ni foam (Table , entry 3) with a crystalline‐RuO 2 /Ni foam anode obtained by annealing the former hydrous species (Table , entry 3).…”

“…These authors reported the combination of a cathode composed of stable hydrous RuO 2 NPs/Ni foam (Table , entry 3) with a crystalline‐RuO 2 /Ni foam anode obtained by annealing the former hydrous species (Table , entry 3). This combination of electrodes afforded an efficient alkaline electrolyzer, achieving overall values of η 0 ≈170 mV and η 10 =273 mV; these values outperform those obtained with (Pt/C)/Ni and IrO 2 /Ni as cathodic and anodic electrode materials, respectively . In a related example, Song and co‐workers recently described the use of partially hydrous RuO 2 NPs embedded in a C matrix as a multifunctional electrocatalyst, with the HER (Table , entry 29; Table , entry 31) and OER (Table , entry 7; Table , entry 8) as two of its functionalities (see Sections 3 and 4 for more details).…”