One-pot pyrolysis synthesis of highly active Ru/RuOX nanoclusters for water splitting

Using simple methods to obtain efficient catalysts has been a long-standing goal for researchers. In this work, the employment of a one-pot pyrolysis reaction to achieve molecular confinement, has led to the preparation of ruthenium (Ru)-based nanoclusters in a carbon matrix. A unique feature of the synthetic approach employed is that solvent and substrates were calcined together. As solvent evaporates, during calcination, the substrates form a dense solid which has the effect of limiting the aggregation of Ru centers during the carbonization process. The catalyst prepared in this simple manner showed an impressively high activity with respect to the hydrogen/oxygen evolution reaction (HER/OER). The Ru nanoclusters (Ru NCs), as the hydrogen evolution reaction (HER) catalysts, require ultralow overpotentials of 5 mV and 5.1 mV at -10 mA center dot cm(-2) in 1.0 M KOH, and 0.5 M H2SO4, respectively. Furthermore, the catalyst prepared by the one-pot method has higher crystallinity, a higher Ru content and an ultrafine cluster size, which contributes to its exceptional electrochemical performance. Meanwhile, the RuOX nanoclusters (RuOX NCs), obtained by oxidizing the aforementioned Ru NCs, exhibited good oxygen evolution reaction (OER) performance with an overpotential of 266 mV at 10 mA center dot cm(-2). When applied to overall water splitting, Ru/RuOX nanoclusters as the cathode and anode catalysts can reach 10 mA center dot cm(-2) at cell voltages of only 1.49 V in 1 M KOH.

Automated summary

In this study, ruthenium (Ru)-based nanoclusters were prepared in a carbon matrix using a one-pot pyrolysis reaction, leading to efficient catalysts with high activity for hydrogen/oxygen evolution reactions. The catalyst showed ultralow overpotentials for HER and OER, and when applied to overall water splitting, the Ru/RuOX nanoclusters exhibited exceptional performance at low cell voltages.