Ultrathin Carbon Coating and Defect Engineering Promote RuO₂ as an Efficient Catalyst for Acidic Oxygen Evolution Reaction with Super‐High Durability

Abstract

Developing acid‐stable electrocatalysts with high activity for the oxygen evolution reaction (OER) is of paramount importance for many energy‐related technologies. This work reports that ultrathin nitrogen‐doped carbon coated oxygen‐vacancy (Vo·) rich RuO2 nanoparticles on carbon nanotubes (CNTs) (NC@Vo·‐RuO2/CNTs‐350), synthesized through the controlled calcination in air, is an efficient acid‐stable electrocatalyst for the OER. It only needs an overpotential of 170.0 mV to drive 10.0 mA cm−2 and shows excellent stability with no distinguishable activity loss observed for >900 h. Its mass activity is >110 times higher than the commercial RuO2. In particular, an electrolyzer assembled with this catalyst shows a record‐low cell voltage of 1.45 V to deliver 10.0 mA cm−2 and exhibits a low performance drop for >1000 h. The NC@Vo·‐RuO2/CNTs‐350 also shows super‐high catalytic activities and excellent stabilities for OER in neutral and alkaline media. DFT calculations indicate that its high catalytic activity mainly arises from the strong electronic coupling between RuO2 and NC/CNTs, which increases the oxidation state and catalytic activity of Ru at the active site and improves the stabilities of lattice oxygen and surface Ru during the OER processes. The presence of Vo· can strengthen the electronic coupling between RuO2 and NC/CNTs.

High activity and excellent durability of oxygen-vacancy-rich ruthenium manganese oxide solid-solution nanowires for the oxygen evolution reaction in acidic media

“…3a shows that the OER catalysed by the V-Ru x Mn 1− x O 2 NWs has an onset potential of 1.37 V ( E on ) and they only need an overpotential of ∼200.0 mV to drive a current density of 10 mA cm −2 ( η 10 ). The OER activity of the V-Ru x Mn 1− x O 2 NWs is much higher than those of com-RuO 2 ( E on = 1.44 V and η 10 = 302.0 mV, close to the reported values 10,24 ) and commercial IrO 2 (com-IrO 2 , E on = 1.47 V and η 10 = 330 mV, close to the reported values 25,26 ). In particular, the η 10 value of V-Ru x Mn 1− x O 2 NWs is lower than that of other acidic OER catalysts reported recently, such as Ni–RuO 2 (214.0 mV) 18 and Si-RuO x @C (220.0 mV) 24 (Table S1†).…”

“…3 Tremendous work has demonstrated that the electronic structure of the active sites is the major factor determining the activity of the catalysts, since it governs the adsorption of reactants, the transformation of intermediates, and the desorption of products. 10 Generally, the methods used for the modulation of the electronic structure of the active sites include metal doping, 11 vacancy generation, 12 active facet control, 13 heterostructuring, 7 etc. As reported previously, metal doping can optimize the electronic structure of the active sites at the catalyst surface through charge redistribution, which lowers the energy barrier of the rate-determining step (RDS) for the OER.…”

Platinum Nanoparticles Bonded with Carbon Nanotubes for High-Performance Ampere-Level All-Water Splitting

“…37 However, the O1 peak associated with metal oxides and the O3 peak belonging to lattice-defective oxygen on the metal surface are all absent, which can illustrate there are no platinum oxides existing in Pt-NPs-bonded@CNT. 38 This result demonstrates that divalent platinum is formed by the formation of chemical bonds between platinum and carbon (Pt−C) in carbon nanotubes. The metallic state of platinum is related to the platinum nanoparticles bonded in carbon nanotubes.…”

Design Strategies of Active and Stable Oxygen Evolution Catalysts for Proton Exchange Membrane Water Electrolysis

“…In this approach, the passivating material should be stable under the PEMWE operating conditions of harsh acidic electrolytes and a strong oxidative potential range. Viable passivation materials include TiO 2 , − carbon, − and other metal species. − For example, Tran-Phu et al prepared Co 3 O 4 catalysts passivated with a TiO 2 layer and investigated the impact of the TiO 2 layer thickness on the OER stability. When the thickness of the TiO 2 layer was 4.4 nm, the catalyst achieved the maximum stability, as identified by the potential retention time of 75 h at the current density of 10 mA ( t 10 ).…”