Preparation Of Ru@RuO₂ Core-shell Nanospheres With Strains For Oxygen Evolution Reaction Electrocatalysis

As a vast and recyclable resource,water can be electrochemically splitted into clean hydrogen energy and chemical oxygen by an electrolyzer to achieve an environment-friendly energy cycle.As one of the semi-reactions of electrochemical water splitting,the kinetics of oxygen evolution reaction(OER)is slow,so it is necessary to develop an efficient OER electrocatalysis.The most suitable OER electrocatalysis Ru-based catalyst still has the problem of strong adsorption of the active intermediate*OOH,therefore,it is urgent to tune the electronic structure of Ru(IV)active site to improve the catalytic activity.Herein,for the first time we engineer the charge density of Ru(IV)using laser liquid irradiation by creating tensile strain in the RuO₂ shell of Ru@RuO₂ core-shell nanoparticles(namely,Ru@RuO₂-L)without any heteroatoms doping.High-resolution spectroscopic characterizations confirm the presence of av 6%tensile strain in Ru-O bonds which results in an effective reducing of the charge density of Ru(IV).The resultant Ru^X+(4<X<5)active sites greatly accelerate the oxygen evolution reaction(OER)kinetics in acidic and alkaline electrolyte.In acid electrolyte,the overpotential of at 10 m A cm^-2 is only 191 m V,outperforming the benchmark Ru O2 catalyst,and also among the lowest value for efficient Ru-based electrocatalysts without any heteroatoms doping reported so far.The specific activity and mass activity are also greatly enhanced by 4.2 and 17.7 folds compared to Ru O2,respectively.The OER catalytic performance in alkaline environment is also improved.There are two main reasons for the improvement of OER activity:(1)The reduced charge density of Ru(IV)lowers the adsorption energy of*OOH.(2)The existence of ruthenium metal core rapids the charge transport.Ru@Ru O2-L is also used as anode catalyst for overall water splitting in acid and alkaline media,requiring only 1.45 V and 1.56 V to deliver a current density of 10 m A cm^-2 respectively,along with Pt/C as the cathode catalyst.