Robust Interface Ru Centers for High‐Performance Acidic Oxygen Evolution

Abstract

RuO2 is considered as the state‐of‐the‐art electrocatalyst for the oxygen evolution reaction (OER) in acidic media. However, its practical application is largely hindered by both the high reaction overpotential and severe electrochemical corrosion of the active centers. To overcome these limitations, innovative design strategies are necessary, which remains a great challenge. Herein, robust interface Ru centers between RuO2 and graphene, via a controllable oxidation of graphene encapsulating Ru nanoparticles, are presented to efficiently enhance both the activity and stability of the acidic OER. Through precisely controlling the reaction interface, a much lower OER overpotential of only 227 mV at 10 mA cm−2 in acidic electrolyte, compared with that of 290 mV for commercial RuO2, but a significantly higher durability than the commercial RuO2, are achieved. Density functional theory (DFT) calculations reveal that the interface Ru centers between the RuO2 and the graphene can break the classic scaling relationships between the free energies of HOO* and HO* to reduce the limiting potential, rendering an enhancement in the intrinsic OER activity and the resistance to over‐oxidation and corrosion for RuO2.

Modulating electronic structure of metal-organic frameworks by introducing atomically dispersed Ru for efficient hydrogen evolution

“…Among them, hydrogen is considered as the most promising substitute because of its high gravimetric energy density as well as zero CO 2 emission [5][6][7][8] . Recently, electrochemical water splitting, generally including two half-reactions, hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), has aroused increasing interests [9][10][11][12] . HER, producing low-cost and high purity hydrogen gas, is the hot spot in energy-conversion technologies and arouses increasing interests.…”

Rare-earth-regulated Ru-O interaction within the pyrochlore ruthenate for electrocatalytic oxygen evolution in acidic media

“…Previous theoretical studies demonstrate that the OER intrinsic activity is strongly related to the metal-oxygen binding strength according to adsorbate evolution mechanism theory [1,49]. The optimal OER catalysts ought to have neither too strong nor too weak metal-oxygen binding strengths [17,30]. It is generally accepted that the metal-oxygen binding strength could be regulated by modulating the d band center of the active sites [35,50].…”

“…Compared with iridium dioxide, ruthenium dioxides possess higher activity and lower expense [15]. However, ruthenium dioxide is easily oxidized to RuO 4 at high working potential [16,17], which is expected to result in loss of active sites and instability during the OER process.…”

Manipulating Interfaces of Electrocatalysts Down to Atomic Scales: Fundamentals, Strategies, and Electrocatalytic Applications

“…As reveled by DFT calculations, the interface Ru centers allowed one to break the *HOO/*HO scaling relations to reduce the overpotential, giving rise to a significantly improvement in the OER activity and resistance to corrosion and over‐oxidation for RuO 2 . [ 176 ] Likewise, cytomembrane‐inspired Ni‐N‐O heterointerface between strongly interacted Ni 3 N and NiO NPs, contributed to highly efficient reactive sites with a sixfold increase in OER efficiency than primary Ni 3 N NPs. DFT simulations further exhibited a maximum of 85% reduction of the energy barrier over the RLS (*OOH formation) during the OER process (Figure 6e,f).…”