Ruthenium nanoclusters anchored on cobalt phosphide hollow microspheres by green phosphating process for full water splitting in acidic electrolyte

Transition metal phosphide(TMP) based electrocatalysts possessing special crystal and electronic structures attract broad attention in the field of electrocatalysis.Immense effort is made to optimize TMP catalysts aiming to satisfy the electrochemical catalysis performance.In this work,an environmentally friendly in situ green phosphating strategy and spatial limiting effect of the RuCo precursor is employed to fabricate the ruthenium nanoclusters anchored on cobalt phosphide hollow microspheres(Ru NCs/Co_(2)P HMs).The obtained Ru NCs/Co_(2)P HMs electrocatalysts exhibit high hydrogen evolution reaction(HER) activity at wide pH ranges,which require an overpotential of 77 mV to achieve the current density of 10 mA/cm^(2) in 0.5 mol/L H_(2)SO_(4) and 118 mV in 1.0 mol/L KOH.Besides,the multifunctional Ru NCs/Co_(2)P HMs exhibit good oxygen evolution reaction(OER) activity with an overpotential of 197 mV to reach the current density of 10 mA/cm^(2) in 0.5 mol/L H_(2)SO_(4),which is below that of the commercial RuO_(2) electrocatalyst(248 mV).A two-electrode electrolyzer is assembled as well,in acid electrolyte,it achieves a current density of 10 mA/cm^(2) at a voltage of 1.53 V,which is superior to that of the benchmark of precious metal-based electrolyzer(1.58 V).

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·cm^(-2) in 1.0 M KOH,and 0.5 M H_(2)SO_(4),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 RuO_(x) nanoclusters(RuO_(x) NCs),obtained by oxidizing the aforementioned Ru NCs,exhibited good oxygen evolution reaction(OER)performance with an overpotential of 266 mV at 10 mA·cm^(-2).When applied to overall water splitting,Ru/RuO_(x) nanoclusters as the cathode and anode catalysts can reach 10 mA·cm^(-2) at cell voltages of only 1.49 V in 1 M KOH.